National Building Specification.

shawlaskewvilleΠολεοδομικά Έργα

29 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

222 εμφανίσεις


1




Residential Development, Ballygowan Rd, Belfast

-

2948
























National Building Specification
.


Parts:


E10
,

E20
,

E30
,

E40,

E41,

E60
,


G10


2




E05 IN SITU CONCRETE CONSTRUCTION GENERALLY


To be read with Preliminaries/General

conditions.:


110

ARRANGEMENT OF INFORMATION
: The different parts of in situ concrete construction
are specified in separate sections as follows:



E10 In situ concrete mixes, casting and curing



E20 Formwork



E30 Reinforcement



E40 Designed join
ts



E41 Worked finishes/Cutting



E60 Precast/Composite concrete floors/roof decks



Clauses dealing with particular aspects of certain types of construction may thus be
dispersed over several sections.


220

DESIGN OF STRUCTURAL CONCRETE:

Standa
rds:


-


Design: To BS 8110 & BS 8007


-


Reinforce
ment schedules: To BS 449,BS 4482, BS 4482,BS 4483 or BS 6744 and BS 8666 for
reinforcement bending.


300

LEVELS OF STRUCTURAL CONCRETE FLOORS
:


As Preliminaries clause A33/370.


310

SURFACE REGULARITY

OF CONCRETE STRUCTURAL FLOORS
:

Sudden irregularities not permitted. When measured with a slip gauge to BS 8204:Part 1 or
2, Figure 3 or equivalent, the variation in gap under a straightedge (with feet) placed
anywhere on the surface to be not more
than the following:


-

Floors which are to be self
-
finished, and floors to receive sheet or tile finishes directly
bedded in adhesive:



5 mm under a 3 m straightedge



2 mm under a 1 m straightedge


-

Floors to receive screeds/toppings/beds up to 50 mm th
ick:



10 mm under a 3 m straightedge.


-

Floors to receive mastic asphalt flooring or underlay laid over mastic asphalt levelling
coat(s): 10 mm under a 3 m straightedge.


-

Floors to receive mastic asphalt flooring or underlay laid direct: To the same su
rface
regularities as defined in clause M11/760.









3

E10

MIXING/ CASTING/ CURING IN SITU CONCRETE




To be read with Preliminaries/ General conditions.





CONCRETE


101

SPECIFICATION


-

Concrete generally: To BS 8500
-
2.


-

Exchange of information:
Provide concrete producer with information required by BS 8500
-
1,
clauses 4 and 5.



130

NORMAL DESIGNED CONCRETE FOR FOUNDATIONS, SLABS


-

Embedded metal: refer to section E30 of specification


-

Compressive strength class (cylinder/ cube minimum): C2
8/35 N/mm2.


-

Aggregates:



-

Size (maximum): 20mm.



-

Coarse aggregates: to B.S. 882.



-

Sand: to B.S. 882.


-

Limiting values for composition:



-

Water/cement ratio (maximum): 0.6.



-

Cement/ combination content (minimum): 300kg/cu m .


-

Cement: P
C.


-

Maximum total percentage of chloride ions by mass of cement: 0.4% .


-

Admixtures: none for ground floor
slab, use 4.5 +/
-

1.5% Air content requirement ( Air
Entrainme
nt concrete) for Basement Floor


-

Basement slab to have a concrete char
acteristic strength of 35N/mm2 at 28 days with a 50: 50
OPC:
GGBS
Slab blend mix to reduce cracking.


-

Information to be provided by the producer: As BS 5328: Part3, Clause 3.



Sampling and testing in accordance with clause 510.


131

NORMAL DESIGNED C
ONCRETE FOR LINTELS, BE
AMS,
COLUMNS,
MANHOLE COVER
SLABS, BASES,BASEMENT DECK SLAB and BASEMENT RETAINING WALL.


-

Embedded metal: refer to section E30 of specification


-

Compressive strength class (cylinder/ cube minimum): C28/35 N/mm2.


-

Aggregates:



-

Size (maximum): 10mm.

(Except deck slabs & Walls to be 20mm Aggregrate)



-

Coarse aggregates: to B.S. 882.



-

Sand: to B.S. 882.


-

Limiting values for composition:



-

Water/cement ratio (maximum): 0.65.



-

Cement/ combination content (minimum): 315
kg/cu m .


-

Cement: PC.


-

Maximum total percentage of chloride ions by mass of cement: 0.4% .


-

Admixtures: none.


-

Information to be provided by the producer: As BS 5328: Part3, Clause 3.



Sampling and testing in accordance with clause 510.


132

NORMAL DESIGNED CONCRETE FOR MUD MAT, CAVITY FILL, FILLING ETC.


-

Embedded metal: refer to section E30 of specification


4


-

Compressive strength class (cylinder/ cube minimum): C8/10 N/mm2.


-

Aggregates:



-

Size (maximum): 20mm.



-

Coarse aggregates: to

B.S. 882.



-

Sand: to B.S. 882.


-

Limiting values for composition:



-

Water/cement ratio (maximum): 0.8.



-

Cement/ combination content (minimum): 180kg/cu m .


-

Cement: PC.


-

Maximum total percentage of chloride ions by mass of cement: 0.4% .


-

A
dmixtures: none.


-

Information to be provided by the producer: As BS 5328: Part3, Clause 3.



Sampling and testing in accordance with clause 510.



150

PRESCRIBED CONCRETE MIX FOR FLOOR SCREEDS


-

Source of prescribed concrete: mixed using forced acti
on mixer.


-

Fibres: Defribrillated Polypropylene Fibres


-

Aggregates:



-

Size (maximum): 6mm (single size crushed rock)



-

Type/ Density: normal



-

Coarse recycled aggregates: to B.S.882 .



-

Fine aggregate grading: sharp sand to B.S. 882.


-

Cement
/ combinations: ordinary Portland.



-

Standard strength class: PC42.5.


-

Mix proportions:



-

Cement/ combination content: 1 part



-

Coarse aggregate: 1.5 parts



-

Fine aggregate: 3 parts



-

Water:cement ratio: 25mm slump.





MATERIALS, BATCHING AND
MIXING


215

READY
-
MIXED CONCRETE must be

used for basement slab
,

columns, Stairwell/lift shaft
walls(basement to ground level),deck slab and downstand

beams.


-

Production plant: Currently certified by a body accredited by UKAS to BS EN 45011 for produ
ct
conformity certification of ready
-
mixed concrete, or meeting the requirements of the NACCB,
Category 2 for product conformity.


-

Source of ready
-
mixed concrete: Obtain from one source unless otherwise approved.



-

Name and address of depot: Submit be
fore any concrete is delivered.



-

Delivery notes: Retain for inspection.


-

Declarations of nonconformity from concrete producer: Notify immediately.


255

CEMENTS

The following abbreviations apply;

PC42.5 Portland cement, Class 42.5 (in lieu of OPC)





221

INFORMATION ABOUT PROPOSED CONCRETES


-

Submit when requested:



-

Details listed in BS 8500
-
1, clause 5.2.


5



230

INTERRUPTION OF SUPPLY DURING CONCRETING


-

Elements without joints: Where elements are detailed to be cast in a single pour without
joints,
make prior arrangements for a back
-
up supply of concrete.


-

Elsewhere:



-

Preparation: Manage pour to have a full face, and have materials available to form an emergency
construction joint while concrete can still be worked.



-

Before pour is c
ompleted: Submit location and details of joint, make proposals for joint
preparation.


305

NATURAL AGGREGATES FOR DESIGNED / PRESCRIBED MIXES:


-

To give a drying shrinkage of concrete not exceeding 0.075% when tested to B.S.:812 Part 120.


315

AG
GREGATES FOR EXPOSED VISUAL CONCRETE


-

Limitations on contaminants: Free from absorbent particles which may cause 'pop
-
outs', and other
particles such as coal and iron sulfide which may be unsightly or cause unacceptable staining.


-

Colour: Consistent.


-

Supply: From a single source and maintained throughout the contract.


-

Samples: Submit on request.


325

MATERIALS FOR EXPOSED VISUAL CONCRETE

-

Alterations to sources, types and proportions: Submit proposals.


355

RISK OF ALKALI SILICA REACTION IN

DESIGNED / PRESCRIBED MIXES:


-

Take one of the precautions specified for Designed mixes in clause 5.5.7 of BS 5328: Part 2. Inform
CA if this necessitates a change in specification. Submit evidence of compliance to CA before
making concrete for use in th
e Works.


415

ADMIXTURES

-

Calcium chloride and admixtures containing calcium chloride: Do not use.

-

To BS 5075

-

Use only if approved, and then in accordance with manufacturers recommendations.

-

Ensure that admixtures are compatible with all other materials
, including other admixtures.

-

Admixture required for air entrained concrete for basement slab.


429

NON FERROUS FIBRES


-

Requirement: crack control in screeds.


-

Material: Defibrillated polypropylene fibres.


-

Addition rate 0.9kg/cu m.


-

Dispersion

in fresh concrete: Uniform without balling.


490

PROPERTIES OF FRESH CONCRETE

-

Adjustments to suit construction process: Determine with concrete producer. Maintain conformity to
the specification.





PROJECT TESTING/ CERTIFICATION


505

PROJECT TES
TING OF CONCRETE




6


-

Testing: To BS EN 206
-
1, Annex B and BS 8500
-
1, Annex B.



-

Nonconformity: Obtain instructions immediately.


-

Recording: Maintain complete correlated records including:



-

Concrete designation.



-

Sampling, site tests, and identif
ication numbers of specimens tested in the laboratory.



-

Location of the parts of the structure represented by each sample.



-

Location in the structure of the batch from which each sample is taken.


508

REGULAR PROJECT TESTING


-

Tests: Cube tests
(compressive strength testing required).


-

Sampling:



-

Point: Take samples from ready mix lorry chute at dispatch point on site, part way through load
discharge.



-

Rate: For compressive strength testing: take one sample per every 6 cu m but not more
than 3
samples per day.


-

Other requirements: Information to be provided by the producer: As BS5328: Part 3, clause 3.


520

TESTING LABORATORY


-

Laboratory: Accredited by UKAS / NAMAS or other national equivalent.


-

Name and UKAS reference number: S
ubmit well in advance of making trial mixes or concrete for
use in the works.


530

TESTS RESULTS


-

Submission of reports: Within one day of completion of each test.


-

Number of copies: 1 c
opy of reports to be dispatched to the engineer.


-

Reports on

site: A complete set, available for inspection.


550

BROKEN CUBES FROM FAILED STRENGTH TESTS


-

Nonconformity: Keep separately the pieces of each cube which fail to meet the conformity
requirements for individual results.


-

Period for keeping cubes:
Obtain instructions.


580

FAILURES



If a concrete sample fails to achieve specified criteria or to pass specified tests, inform the CA
without delay and submit:



Confirmation of the validity of the test results, and/or




Proposals for further tests

to assess the strength of the concrete in the structure, as set out in BS
6089, and/or



Proposals for rectification.



Obtain approval of all such evidence and proposals before proceeding. The CA may issue
instructions for the work to be stopped or delay
ed until reasons for the failure have been established,
possible consequences
assessed

and appropriate preventative and remedial measures taken.


581

FAILURES



Where ever the specified sampling, testing and compliance procedures show that a concrete m
ix is
not in accordance with the specification(even if the work is eventually accepted), and measures are
taken to help establish whether or not the work is acceptable, such measures:



Will be at the expense of the contractor, and will not be considered a
s grounds for an extension in
time.




7





PLACING AND COMPACTING


620

TEMPERATURE OF CONCRETE


-

Application: pouring during summer months.


-

Objective: Limit maximum temperature of concrete to minimize cracking during placing,
compaction and curing.
Take account of:



-

High temperatures and steep temperature gradients: Prevent build
-
up during first 24 hours after
casting. Prevent coincidence of maximum heat gain from cement hydration with high air
temperature and/ or solar gain.



-

Rapid changes in
temperature: Prevent during the first seven days after casting.




630

PREMATURE WATER LOSS


-

Requirement: Prevent water loss from concrete laid on absorbent substrates.


-

Underlay: Select from:




Polyethylene sheet: 250 micrometres thick.




Buildi
ng paper: To BS 1521, grade B1F.


-

Installation: Lap edges 150 mm.


640

CONSTRUCTION JOINTS


-

Location of joints: submit details of proposed locations and obtain approval before proceeding.


-

Preparation of joint surfaces: carefully brush and spray
surface while concrete is still green to
remove surface laitance and expose aggregate finish. Obtain approval for any alternative method.
Surface to be clean and damp when fresh concrete is placed against it.


648

ADVERSE TEMPERATURE CONDITIONS


-

Requ
irement: Submit proposals for protecting concrete when predicted ambient temperatures
indicate risk of concrete freezing or overheating.


650

SURFACES TO RECEIVE CONCRETE


-

Cleanliness of surfaces immediately before placing concrete: Clean with no deb
ris, tying wire
clippings, fastenings or free water.


660

INSPECTION OF SURFACES


-

Notice: Give notice to allow inspections of reinforcement and surfaces before each pour of concrete.


-

Period of notice: Obtain instructions.



670

TRANSPORTING


-

General: Avoid contamination, segregation, loss of ingredients, excessive evaporation and loss of
workability. Protect from heavy rain.


-

Entrained air: Anticipate effects of transport and placing methods in order to achieve specified air
content.


6
80

PLACING


-

Records: Maintain for time, date and location of all pours.


-

Timing: Place as soon as practicable after mixing and while sufficiently plastic for full compaction.


-

Temperature limitations for concrete: 30°C (maximum) and 5°C (minimum), un
less otherwise
specified. Do not place against frozen or frost covered surfaces.


8


-

Continuity of pours: Place in final position in one continuous operation up to construction joints.
Avoid formation of cold joints.


-

Discharging concrete: Prevent uneven
dispersal, segregation or loss of ingredients or any adverse
effect on the formwork or formed finishes.


-

Thickness of layers: To suit methods of compaction and achieve efficient amalgamation during
compaction.


-

Poker vibrators: Do not use to make concr
ete flow horizontally into position, except where
necessary to achieve full compaction under void formers and cast
-
in accessories and at vertical
joints.


690

COMPACTING


-

General: Fully compact concrete to full depth to remove entrapped air. Continue

until air bubbles
cease to appear on the top surface.


-

Areas for particular attention: Around reinforcement, under void formers, cast
-
in accessories, into
corners of formwork and at joints.


-

Consecutive batches of concrete: Amalgamate without damagin
g adjacent partly hardened concrete.


-

Methods of compaction: To suit consistence class and use of concrete.


720

VIBRATORS


-

General: Maintain sufficient numbers and types of vibrator to suit pouring rate, consistency and
location of concrete.


-

Ex
ternal vibrators: Obtain approval for use.


730

PLASTIC SETTLEMENT


-

Settlement cracking: Inspect fresh concrete closely and continuously wherever cracking is likely to
occur, including the top of deep sections and at significant changes in the depth
of concrete sections.


-

Timing: During the first few hours after placing and whilst concrete is still capable of being
fluidized by the vibrator.


-

Removal of cracks: Revibrate concrete.


810

CURING GENERALLY


-

Requirement: Keep surface layers of co
ncrete moist throughout curing period, including perimeters
and abutments, by either restricting evaporation or continuously wetting surfaces of concrete.


-

Surfaces covered by formwork: Retain formwork in position and, where necessary



to satisfy curin
g period, cover surfaces immediately after striking.


-

Top surfaces: Cover immediately after placing and compacting. If co
vering is removed for finishing
operations, replace it immediately afterwards.


-

Surface temperature: Maintain above 5°C throughout
the specified curing period or four days,
whichever is longer.


-

Records: Maintain details of location and timing of casting of individual batches, removal of
formwork and removal of coverings. Keep records on site, available for inspection.


811

COVE
RINGS FOR CURING


-

Sheet coverings: Suitable impervious material.


-

Curing compounds: Selection criteria:



-

Curing efficiency: Not less than 75% or for surfaces exposed to abrasion 90%.



-

Colouring: Fugitive dye.



-

Application to concrete exposed i
n the finished work: Readily removable without disfiguring the
surface.


-

Application to concrete to receive bonded construction/ finish: No impediment to subsequent
bonding.


9


-

Interim covering to top surfaces of concrete: Until surfaces are in a suitabl
e state to receive
coverings in direct contact, cover with impervious sheeting held clear of the surface and sealed
against draughts at perimeters and junctions.




812

PREVENTING EARLY AGE THERMAL CRACKING


-

Deep lifts or large volume pours: Submit p
roposals for curing to prevent early age thermal cracking,
taking account of:



-

Temperature differentials across sections.



-

Coefficient of thermal expansion of the concrete.



-

Strain capacity of the concrete mix (aggregate dependent).



-

Restraint.


820

CURING PERIODS


-

General: Curing periods are in days (minimum).


-

Definition of 't': The average number of degrees Celsius air temperature during the curing period.


-

Curing periods for concrete surfaces which, in the finished building, will b
e exposed to the
elements; concrete wearing surface floors and pavements; water resistant concrete:





Concrete made

Concrete made




using CEM1

using cements




strength class

indicated in




42.5 or 52.5;

BS 8500, table




SRPC

A.17 except those




(
BS 4027)

listed in adjacent





column and





supersulfated cement



_______________________________________________________



Drying winds or dry,

140

180



sunny weather

t+10

t+10



(relative humidity





< 50%)



______________________________________
_____________________




Intermediate

100

140



conditions

t+10

t+10



_______________________________________________________



Damp weather,

100

100



protected from sun

t+10

t+10



and wind (relative



humidity > 80%)





____________________________
___________________________



-

Curing periods for other structural concrete surfaces (cements/



combinations as above):



_______________________________________________________



Drying winds or dry,

80

140



sunny weather

t+10

t+10



(relative humidity






< 50%)




10




Intermediate

60

80



conditions

t+10

t+10




Damp weather

No special

No special



protected from sun

requirements

requirements



and wind (relative



humidity > 80%)





_______________________________________________________


-

Curing pe
riods for concretes using admixtures or other types of



cements/ combinations: Submit proposals.



821

CURING PERIODS
,

in days:


-

Concrete surfaces which in the finished building will be exposed to the elements; concrete
wearing surface floors and pa
vements; watertight concrete:




Concrete made

using PC42.5,

PC52.5, SRPC

Concrete made

using PPFAC,

PBFC, HSBC,

Pfa,ggbs


November

to April

May to

October


10


7


12


10



-

Other structural concrete surfaces: No special requirements if in damp weather
and
protected from sun and wind, otherwise as follows (cements as above):




November

to April

May to

October


6


4


10


7



-

Obtain prior approval for curing periods for mixes using admixtures or other types of
cement.


822

CURING PERIODS
, not less
than:


-

Surfaces which in the finished building will be



exposed to the elements, and wearing



surfaces of floors and pavements,



regardless of weather conditions


10 days


-

Other structural concrete surfaces



5 days


840

PROTECTION


-

Prevent
damage to concrete, including:



-

Surfaces generally: From rain, indentation and other physical damage.



-

Surfaces to exposed visual concrete: From dirt, staining, rust marks and other disfiguration.


11



-

Immature concrete: From thermal shock, physical
shock, overloading, movement and vibration.



-

In cold weather: From entrapment and freezing expansion of water in pockets, etc.





E20

FORMWORK FOR IN SITU CONCRETE




To be read with Preliminaries/ General conditions.





GENERALLY/ PREPARATION


11
0

LOADINGS


-

Requirement: Design and construct formwork to withstand the worst combination of the following:



-

Total weight of formwork, reinforcement and concrete.



-

Construction loads including dynamic effects of placing, compacting and construction

traffic.



-

Wind and snow loads.


132

PROPPING


-

General: Prevent deflection and damage to the structure. Carry down props to bearings strong
enough to provide adequate support throughout concreting operations.


-

Method statement: Submit proposals
for prop bearings and sequence of propping/ re
-
propping and
back
-
propping.





145

PERMANENT FORMWORK


-

Location and materials: Submit proposals.


170

WORK BELOW GROUND


-

Casting vertical faces of footings, bases and slabs against faces of excav
ation: Submit proposals and
obtain consent, it is unlikely that ground conditions will be suitable in this scheme.


-

Casting walls against faces of excavation: Use formwork on both sides.


190

SUBSTRUCTURE FORMWORK FOR SLABS / FOUNDATIONS IF REQUIRED


-

Contractor to submit details for approval; suitable formwork would be block work walling,
constructed on mud
-
matt covered formation, or timber form work construction using plywood of
adequate quality and rigidity to provide true finish to beams, or prop
rietary formwork such as
permaform. Form work must be straight plumb, and rigid, with all joints sealed to prevent grout
loss. Specified cover must be provided in all locations.


200

PROPRIETARY GROUND FLOOR INSULATION



Insulation placed on top of

suspended ground floor slab, between slab and screed. Insulation to
Architects requirements (refer to separate section of specification)





CONSTRUCTION


310

ACCURACY


-

General requirement for formwork: Accurately and robustly constructed to produc
e finished
concrete in the required positions and to the required dimensions.


-

Formed surfaces: Free from twist and bow (other than any required cambers).


12


-

Intersections, lines and angles: Square, plumb and true.


320

JOINTS IN FORMS


-

Requirement
s including joints in form linings and between forms and completed work:


-

Prevent loss of grout, using seals where necessary.


-

Prevent formation of steps. Secure formwork tight against adjacent concrete.


330

INSERTS, HOLES AND CHASES


-

Positions
and details: Submit proposals.


-

Positioning relative to reinforcement: Give notice of any conflicts well in advance of placing
concrete.


-

Method of forming: Fix inserts or box out as required. Do not cut hardened concrete without
approval.




340

K
ICKERS


-

Method statement: Submit proposals including means of achieving quality of concrete consistent
with that specified for the column or wall.



-

Kicker height (minimum): 100 mm.


350

FORM TIES


-

Metal associated with form ties/ devices: Prohib
ited within cover to reinforcement. Compatible with
reinforcement metal.


351

PROHIBITION OF FORM TIES


-

Do not use ties in the following work:



ring beams, lintels.


470

RELEASE AGENTS


-

General: Achieve a clean release of forms without disfigu
ring the concrete surface.


-

Product types: Compatible with formwork materials, specified formed finishes and subsequent
applied finishes. Use the same product throughout the entire area of any one finish.


-

Protection: Prevent contact with reinforcement
, hardened concrete, other materials not part of the
form face, and permanent forms.


480

SURFACE RETARDERS


-

Use: Obtain approval.


-

Reinforcement: Prevent contact with retarder.





STRIKING


510

STRIKING FORMWORK


-

Timing: Prevent any disturb
ance, damage or overloading of the permanent structure.


520

MINIMUM PERIODS
:


-

The following periods (in days) for retaining formwork in position before striking apply to
class 42.5 or sulphate
-

resisting Portland cement concrete with no cement repla
cement
materials or admixtures:



13






Type of

formwork

Average mean of daily minimum

and maximum air temperatures

during the period



16xºC

7xºC

3xºC







Vertical formwork to

columns, walls and

beams



0.5



75



1







Soffit forms to slabs

4

6

8







Props to slabs and

soffit forms to beams


10


15


20







Props to beams

14

21

28



-

Submit details of proposed periods for mixes using admixtures or other types of cement.


521

MINIMUM PERIODS
:

Alternative methods of determining mini
mum periods for retaining
formwork in position may be submitted for approval. Accept responsibility for cost of
checking of proposals by CA and for any testing.





FORMED FINISHES


600

SAMPLES OF FINISHES AVAILABLE FOR INSPECTION


-

Samples available
for inspection: initial sample pour must be carried out for all elements of insitu
concrete work for inspection by engineer to confirm acceptability of standard of workmanship,
which must then be maintained throughout scheme.


610

BASIC FINISH


-

Fair
face finish to basement RC Walls, Columns,Deck & beams.


615

FINISH TO RECEIVE ASPHALT / BITUTHENE TANKING


-

Finish: Even and suitable to receive a tanking membrane.


-

Permissible deviation of surfaces:



-

Sudden irregularities (maximum): 3 mm.



-

Gradual irregularities when measured from underside of a 1 m straight edge, placed anywhere on
surface (maximum): 3 mm.


-

Surface blemishes:



-

Permitted: Blowholes less than 10 mm in diameter.



-

Not permitted: Voids, honeycombing, segregation and oth
er large defects.


-

Projecting fins: Remove.


-

Formwork tie holes: Filled with mortar.



14

620

PLAIN SMOOTH FINISH


-

Finish: Even with panels arranged in a regular pattern as a feature of the surface.


-

Permissible deviation of surfaces:



-

Sudden i
rregularities (maximum): 5 mm.



-

Gradual irregularities when measured from the underside of a 1 m straightedge, placed anywhere
on surface (maximum): 5 mm.


-

Variations in colour:



-

Permitted: Those caused by impermeable form linings.



-

Not permitte
d: Discoloration caused by contamination or grout leakage.


-

Surface blemishes:



-

Permitted: Blowholes less than 10 mm in diameter and at an agreed frequency.



-

Not permitted: Voids, honeycombing, segregation and other large defects.


-

Formwork tie h
oles: In a regular pattern and filled with matching mortar.


630

FINE SMOOTH FINISH


-

Finish: Smooth and even. Panels to be as large as is practicable and arranged in a regular pattern as
a feature of the surface.


-

Permissible deviation of surfaces
:



-

Sudden irregularities (maximum): 3 mm.



-

Gradual irregularities when measured from the underside of a 1 m straightedge, placed anywhere
on surface (maximum): 3 mm.


-

Variations in colour:



-

Permitted: Those caused by impermeable form linings.



-

Not permitted: Discoloration caused by:




Contamination or grout leakage.




Replacement of formwork panels.


-

Cover spacers: must obtain engineers approval prior to using.


-

Surface blemishes:



-

Permitted: Blowholes less than 5 mm in diameter and a
t an agreed frequency.



-

Not permitted: Voids, honeycombing, segregation and other defects.


-

Formwork tie holes: not permitted.



E30

REINFORCEMENT FOR IN SITU CONCRETE




To be read with Preliminaries/ General conditions.





REINFORCEMENT


110

QU
ALITY ASSURANCE OF REINFORCEMENT


-

Standards:



-

Reinforcement: To BS 4449, BS 4482, BS 4483 or BS 6744.



-

Cutting and bending: To BS 8666.


-

Source of reinforcement: Companies holding valid certificates of approval for product conformity
issued by th
e UK Certification Authority for Reinforcing Steels (CARES).


140

PLAIN BAR REINFORCEMENT


-

Standard: To BS
4449
.


-

Strength grade: 250.



15

150

RIBBED BAR REINFORCEMENT


-

Standard: To BS 4449.


-

Strength grade:
B500
.


210

STANDARD FABRIC REIN
FORCEMENT


-

Standard: To BS 4483.






WORKMANSHIP


310

CUTTING AND BENDING REINFORCEMENT


-

General: To schedules and to BS 8666.


-

Bending on site, including minor adjustments: do not bend when below 5 degree C without prior
approval. Steel may be
warmed to not more than 100 deg C. Do not re
-
bend bars without approval.
Tag bundles of reinforcement with labels to BS 4466


320

PROTECTION OF REINFORCEMENT


-

Dropping from height, mechanical damage and shock loading: Prevent.


-

Cleanliness of reinf
orcement at time of pouring concrete: Free from corrosive pitting, loose
millscale, loose rust and contaminants which may adversely affect the reinforcement, concrete, or
bond between the two.



410

LAPS OR SPLICES


-

Details not shown on drawings: Ob
tain instructions.


425

LAPS NOT DETAILED ON DRAWINGS


-

Laps in bar reinforcement (minimum): 300mm


-

Laps in fabric reinforcement (minimum): 250mm.


-

Laps at corners: Avoid four layer build
-
up.


430

WELDED JOINTS


-

Site welding: _not permitted
._____ .


451

FIXING REINFORCEMENT


-

Standard: To BS 7973
-
1 and
-
2.


-

Installation: In addition to any spacers and chairs shown on drawings or schedules, provide adequate
support, tie securely and maintain the specified cover.


-

Tying:



-

Wire typ
e: 16 gauge black annealed. Use stainless steel wire for stainless steel reinforcement.



-

Ends of tying wire: Prevent intrusion into the concrete cover. Remove loose ends.


-

Compatibility of metals: Prevent contact between ordinary carbon steel and stai
nless or galvanized
reinforcement.


470

TOLERANCES ON COVER


-

Definition of nominal cover to BS 8500
-
1: Minimum cover plus tolerance for fixing.


-

Tolerance (maximum): 5mm


-

Checking specified cover dimensions: Before concreting check that cover di
mensions will be
achieved.




16

480

NOMINAL COVER TO REINFORCEMENT


-

Top face: 30mm minimum

superstructure / 40
mm minimum substructure.


-

Formed faces:
30mm minimum superstructure / 40
mm minimum substructure.


(Use Engineers drawings as prefe
rence)


510

RUST STAINING


-

Staining of surfaces of concrete which will be exposed to view in the finished work: Prevent.


520

COVER METER SURVEY


-

Purpose of survey: To check positions of reinforcement and that the specified cover has been
achie
ved. If any site inspections give rise to concerns with respect to adequacy of cover, engineer /
architect may request a cover meter survey.


-

Type of cover meter: A magnetic induction digital display type selected to suit arrangement and
type of reinforc
ement.


-

Use: In accordance with recommendations of BS 1881
-
204 and manufacturer as appropriate to yield
accurate results.


-

Surveyor: Experienced with cover meter surveys.


-

Calibration: At the outset and thereafter regularly at 45 minute (maximum) int
ervals.


-

Locations for checking: Include beams, lintels and all faces exposed to the weather in the finished
structure.


-

Timing: As soon as practicable after casting.



-

Notification: Give adequate notice.


-

Results: Submit. Notify immediately where
specified cover has not been achieved.




E40

DESIGNED JOINTS IN IN SITU CONCRETE




To be read with Preliminaries/ General conditions.



120

CONSTRUCTION/ MOVEMENT JOINTS GENERALLY


-

Accuracy: Position and form joints accurately, straight, well
-

alig
ned and truly vertical or horizontal
or parallel with setting out lines of the building.


-

Modifications to joint design or location: Submit proposals.


-

Placing concrete to form movement joints:



-

Maintain effectiveness of joints. Prevent concrete ent
ering joints or penetrating or impregnating
compressible joint fillers.



-

Do not place concrete simultaneously on both sides of movement joints.


132

JOINTS IN FLOOR SCREED


-

Proposed positions of butt joints in screed must be agreed with Architect
prior to commencement.


210

FORMED JOINTS


-

Forms/ stop ends generally: Rigid and grout
-
tight.


-

Forms/ stop ends for projecting continuity reinforcement: To accommodate bars or fabric without
temporary bending or displacement.


211

FORMED JOINT
S IN CONCRETE WEARING SURFACES


-

Temporary forms: Square edged with a steel top surface.


-

Placing concrete: Compact thoroughly at edges to give level, closely abutted joints with no lipping.


17


230

PREPARATION OF CONSTRUCTION JOINTS


-

Roughening of j
oint surfaces: Select from:



-

Brushing and spraying: Remove surface laitance and expose aggregate finish while concrete is
still green.



-

Other methods: Submit proposals.


-

Condition of joint surfaces immediately before placing fresh concrete: Clean a
nd damp.


260

SAWN CRACK INDUCING GROOVES


-

Groove dimensions:



-

Depth: 5


10mm .



-

Width: As narrow as practicable.


-

Sawing: Sufficiently early to prevent random cracking (within 24 hours of casting slab) and to
produce strong, well defined ar
rises.


-

Groove filling: hot pour ashphalt.


410

TIE BARS


-

Standard: To BS 4449,


-

Strength grade: 250 N/mm2.


-

Cleanliness: Free from corrosive pitting, loose millscale, loose rust and contaminants which may
adversely affect the tie bars, reinfo
rcement, concrete, or bond between the two.


-

Position: Centred on joint.




430

DOWEL BARS


-

Standard: To B.S. 4449


-

Product form: Plain.


-

Strength grade: 250N/mm2


-

Properties: Perfectly straight, with sawn (not sheared) ends.


-

De
-
bonding:

Achieve effective de
-
bonding of each bar


-

Material: de
-
bonding compound or plastic sleeve, incorporatin
g 20mm compressible material at
ends of all bars.


-

Position: At right angles to and centred on joint.


590

INSPECTION OF TIED AND PARTIALLY TIE
D JOINTS


-

Purpose: To determine whether shrinkage is concentrated at occasional joints.


-

Timing: At intervals from one month after casting of slab for duration of works.


-

Joints that have opened significantly more than the average: Submit proposals f
or grouting.



E41

WORKED FINISHES TO IN SITU CONCRETE




To be read with Preliminaries/ General conditions.


150

FINISHING



-

Seek confirmation of approval of finish from Engineer.

Timing
: Carry out at optimum times in
relation to setting and h
ardening of concrete.


-

Prohibited treatments to concrete surfaces:



-

Wetting to assist surface working.



-

Sprinkling cement.


18



210

TAMPED FINISH


-

Surface on completion: tamp surface with edge of board or beam to give an even texture of paralle
l
ribs.


230

BRUSHED FINISH


-

Surface on completion: Light even texture.


240

WOOD FLOATED FINISH


-

Surface on completion: Slightly coarse, even texture with no ridges or steps.


310

SMOOTH FLOATED FINISH


-

Surface on completion: Even with n
o ridges or steps.


320

TROWELLED FINISH


-

Surface on completion: Uniform, smooth but not polished, free from trowel marks and blemishes,
and suitable to receive specified flooring material.


330

TROWELLED FINISH FOR WEARING SURFACES


-

Surface on

completion: Uniform and smooth, free from trowel marks and blemishes.


520

SURFACE SEALER


-

Apply an approved resin sealer to concrete wearing surface floors in accordance with manufacturers
recommendations.


-

Substrate:



-

Moisture content: As rec
ommended by sealer manufacturer. Test relative humidity to BS 8203,
Annex A where required to verify suitability.



-

Condition prior to application: Cured, clean and free from contaminants.


-

Application: Evenly to dry surfaces to form an effective seal
but without a glossy finish.



E60

PRECAST CONCRETE FLOORS / LINTELS




To be read with Preliminaries/ General conditions.






PERFORMANCE SPECIFIED FLOORS/ ROOF DECKS


210

PRECAST FLOOR :



-

Draw
ing reference(s): 2948/10
-
01
/10




-


Overall de
pth (excluding finishes): 200 mm



-

Span: Varies up to maximum of approximately 6.2m



-

Self weight:
Special Density
300 kg/m3



-

Distributed dead load of finishes, fixtures, un
-
located partitions: 200 kg/sq m



-

Distributed im
posed load: varies ; mini
mum = 4
.0 kN/m² / maximum = 7.5Kn/m2



-

Concentrated imposed load(s): 0.9 kN



-

Deflection: not greater than span divided by 360 camber not greater than span
divided by 250


19



-

Basic fire resistance as clause 280: 1 hour.



-

Finish to soffit: Smooth



-

Finish to top surface: Smooth










GENERAL/ PERFORMANCE


240

DETAILING OF PROPRIETARY SYSTEM


-

Installation details: Submit location and assembly drawings showing every aspect of the
construction, incorporated components and features, trimming fo
r voids, holes for services, and
related work by others.


-

Purpose: To allow checking of compatibility with surrounding structure and coordination of
services.


-

Method statement and risk assessment for installation: Submit.


-

Programme: Submit well in

advance of construction.


250

CONTRACTOR DESIGN


-

Standard: Complete the design in accordance with BS 8110, to meet requirements of this
specification, and contract drawings. The floors must be designed to withstand the worst
combination of dead and
imposed loads, both in the finished building and during construction.


280

BASIC FIRE RESISTANCE


-

Duration: as specified elsewhere.


-

Method of determination: To BS 8110
-
2, section 4 or by testing to BS 476
-
21 or BS EN 1365
-
2.


-

Finishes: Determine

fire resistance without regard to applied finishes.


-

Data: Submit certificates, tabulated data or calculations.





INSTALLATION


310

PRECAST UNITS
:


-

Store units clear of the ground on level bearers correctly positioned.


-

Lift units at designed
lifting points only, using special lifting devices and cradles as
necessary.


-

Set on level bearings ensuring not less than the minimum seating recommended by
manufacturer.


-

Form openings, sinkings and junctions with walls in accordance with pre
-
cast un
its
manufacturer's recommendations, unless detailed otherwise.


-

Do not cut or drill units except as recommended or agreed by manufacturer.


320

CONCRETE INFILL : GROUTING OF JOINTS IN HOLLOWCORE SLABS


-

Concrete: To BS EN 206
-
1 and BS 8500
-
2.



-

Mi
x: C28/35.



-

Aggregate size (maximum): 10mm .


-

Preparation: Thoroughly clean and wet surfaces of pre
-
cast units.


-

Placing: Avoid segregation and compact thoroughly to eliminate voids.



-

Extent: Fill troughs and other holes.


20



-

Finish: Flush with t
op of pre
-
cast units.


-

Protection: Prevent movement of units until concrete has gained sufficient strength.



Units must be grouted immediately after installation and provision of edge protection, before access
is permitted to any follow on trades.


340

LATERAL RESTRAINT STRAPS


-

Preparation: Floors/ roof decks must tightly abut walls.


-

Manufacturer: EXPAMET or Catnic.


-

Product reference: M305 or H1200/100H .


-

Material: GALVANISED STEEL.


-

Size:



-

Section: Minimum 30 x 5 mm cross section.



-

Length: To extend minimum 800 mm from inside face of wall.


-

Form: Both ends cranked 100 mm.


-

Position: at not more than 2.0m centres..


-

Build in:



-

External cavity walls: One cranked end in tight contact with cavity face of wall inner leaf, the
o
ther cranked end grouted into floor deck joint.


350

LEVELS OF STRUCTURAL CONCRETE FLOORS


-

Tolerances: See Preliminaries section A33.


360

SURFACE REGULARITY OF IN SITU TOPPINGS TO COMPOSITE FLOORS:

As

section
E05, clause 310.



F10

BRICK/ BLOCK
WALLING




To be read with Preliminaries/ General conditions.





TYPES OF WALLING

340

CONCRETE COMMON BRICKWORK IN LOADBEARING AND NON LOADBEARING
INTERNAL PARTITIONS AND OUTER LEAF


-

Bricks: To BS 6073
-
1.



-

Type: standard format bricks.



-

Averag
e compressive strength (minimum): 15 N/mm2



-

Work sizes (length x height x thickness): 215x102.5x65mm


-

Mortar: As section Z21.



-

mortar designation (iii) as described in B.S. 5628: part 3: 1985



-

Mix: (cement : sand / 1 : 4 or 5)



-

Additional
req
uirements: drying

shrinkage not exceeding 0.06%.


-

Bond: stretcher bond.


350

CONCRETE COMMON BLOCKWORK IN INTERNAL LOAD BEARING AND NON
LOADBEARING PARTITIONS AND OUTER LEAF


-

Blocks: To BS 6073
-
1.



-

Type: standard

format blocks



-

Average compr
essiv
e strength (minimum): 10.5N/mm2 from 1
st

floor level to roof, 17.5
N
/mm2
below 1
st

floor level to foundation/basement deck slab.



-

Work sizes (length x height x thickness): 440x215x100mm


21


-

Mortar: As section Z21.



-

mortar designation (iii) as desc
ribed in B.S. 5628: part 3: 1985



-

Mix: (cement : sand / 1 : 4 or 5).



-

Additional requirements: drying shrinkage not exceeding 0.06%.


-

Bond: stretcher bond.


360

AUTOCLAVED AERATED CONCRETE (AAC) COMMON BLOCKWORK FOR INTERNAL
PARTITIONS BUILT O
F EXISTING FLOORS IF REQUIRED, (IF PROPOSED INTERNAL
PARTITION ARRANGEMENT IS ALTERED SUCH THAT SUSPENDED FLOORS CANNOT
ACCOMMODATE LOADINGS.


-

Blocks: To BS EN 771
-
4.



-

Manufacturer: quinn
-
lite or finn
-
lite.




Product reference: 7.0 N/mm2 A.A.C. block
s



-

Mean compressive strength (minimum): 7.0 N/mm2




in accordance with B.S. 5628



-

Work sizes (length x width x height): 440x215x100mm



-

Additional requirements: drying shrinkage not exceeding 0.06% .


-

Mortar: As section Z21.



-

mortar designati
on (iii) as described in B.S. 5628: part 3: 1985



-

Mix: (cement : sand / 1 : 4 or 5).


-

Bond: stretcher bond.





TESTING


410

COMPRESSIVE STRENGTH OF MORTAR FOR EACH WALLING TYPE


-

Testing authority: NAMAS (UKAS) approved laboratory


-

Test method
: in accordance with B.S. 5628: part 1: 1992


-

Preliminary tests procedure:(to be carried out by ready mix premix mortar supplier or supplier for
mobile on site batching plant if used)



-

Specimens: (laboratory determination of strengths for mortar desig
nations, (mixes) proposed for
use in the building.)




Number of specimens: 6.




Type: 75mm or 100mm cubes,




Preparation: At least six weeks before walling commences.



-

Specimen testing: Half of specimens at 7 days. Remainder at 28 days.




Retarded
mixes: not allowed on this scheme.



-

Response to result: If mean compressive strength at 28 days is not within the range given below
repeat tests with more suitable sand or next higher designation


-

Site tests procedure: As follows.



-

Number of speci
mens: Six per 150m² of walling or per storey whichever the more frequent.



-

Specimen types: As preliminary test, but prepared during construction.



-

Specimen testing: Half of specimens at 7 days. Remainder at 28 days.




Retarded mixes: Extend curing
periods to include retardation period.


-

Required test mean compressive strength at 28 days (N/mm²): To be within the following range:




Preliminary tests

Site tests





Min.


Min.






N/mm²


N/mm²






(MPa)


(MPa)





3.6



2.5



-

Results: Submit to

engineer for approval.


22


415

FRESH MORTAR CEMENT CONTENT


-

Test method: 6 no. 75mm or 100mm cubes prepared on site for every 150m2 of wall.


-

Test specimens: Test mortar for load bearing
walls
.


-

Results: Submit to engineer for approval.





WORKMAN
SHIP GENERALLY


440

CONDITIONING OF CONCRETE BRICKS/ BLOCKS


-

Autoclaved concrete bricks/ blocks delivered warm from manufacturing process: Do not use. (do
not use until 28 days old)


-

Age of non
-
autoclaved concrete bricks/ blocks: Do not use until a
t least four weeks old.


-

Avoidance of suction in concrete bricks/ blocks: Do not wet.



-

Use of water retaining mortar admixture: Submit details.


460

MORTAR GROUPS


-

Mix proportions: For a specified group select a mix design from the following:



________________________________________________



Group

1

2

3

4



________________________________________________



PC*:lime:sand with or without air entraining additive





1:0
-
0.25:3

1:0.5
-
4.5

1:1:5
-
6

1:2:8
-
9



_________________________________________
_______



Masonry cement:sand containing PC* and lime in approx



ratio 1:1, and an air entraining additive





-

1:3

1:3.5
-
4

1:4.5



_______________________________________________



Masonry cement:sand containing PC* and inorganic



materials other than

lime and air entraining additive





-

1:2.5
-
3.5

1:4
-
5

1:5.5
-
6.5



________________________________________________



PC*:sand and air entraining additive





1:3

1:3
-
4

1:5
-
6

1:7
-
8



________________________________________________



PC* = Portland cement


-

Batching: Mix proportions by volume.


-

Mortar type: Continuous throughout any one type of masonry work.


500

LAYING GENERALLY


-

Mortar joints: Fill vertical joints. Lay bricks, solid and cellular blocks on a full bed.


-

Bond where not specified
: Half lap stretcher.


-

Vertical joints in facework: Even widths. Plumb at every fifth cross joint.


520

ACCURACY


-

Courses: Level and true to line.


-

Faces, angles and features: Plumb.


-

Permissible deviations:



-

Position in plan of any point i
n relation to the specified building reference line and/ or point at
the same level

± 10 mm.



-

Straightness in any 5 m length

± 5 mm.


23



-

Verticality up to 3 m height

± 10 mm.



-

Verticality up to 7 m height

± 14 mm.



-

Overall thickness of walls

± 10
mm.



-

Level of bed joints up to 5 m (brick masonry)

± 11 mm.



-

Level of bed joints up to 5 m (block masonry)

± 13 mm.


535

HEIGHT OF LIFTS IN WALLING USING CEMENT GAUGED OR HYDRAULIC LIME
MORTAR


-

Quoins and advance work: Rack back.


-

Lift height

(maximum): 1.2 m above any other part of work at any time.


-

Daily lift height (maximum): 1.5 m for any one leaf.


545

LEVELLING OF SEPARATE LEAVES


-

Locations for equal levelling of cavity wall leaves: As follows:



-

Every course containing vertic
al twist type ties or other rigid ties.



-

Every third tie course for double triangle/ butterfly ties.



-

Courses in which lintels are to be bedded.


560

COURSING BRICKWORK


-

Gauge: Four brick courses including bed joints to 300 mm.


561

COURSIN
G BRICKWORK WITH EXISTING


-

Gauge: Line up with existing brick courses.


595

LINTELS


-

Bearing: Ensure full length masonry units occur immediately under lintel ends.


610

SUPPORT OF EXISTING WORK


-

Joint above inserted lintel or masonry: Fully c
onsolidated with semidry mortar to support existing
structure.


615

BRICKWORK TO RECEIVE ASPHALT DPC


-

Substrate: Mortar bed finished flush, smooth and level.


620

BLOCK BONDING NEW WALLS TO EXISTING


-

Pocket requirements: Formed as follows:



-

Width: Full thickness of new wall.



-

Depth (minimum): 100 mm.



-

Vertical spacing:




Brick to brick: 4 courses high at 8 course centres.




Block to block: Every other course.


-

Pocket joints: Fully filled with mortar.


635

JOINTING


-

Profile: Co
nsistent in appearance.


645

ACCESSIBLE JOINTS NOT EXPOSED TO VIEW


-

Jointing: Struck flush as work proceeds.


671

FIRE STOPPING


24


-

Avoidance of fire and smoked penetration: Fit tightly between cavity barriers and masonry. Leave
no gaps.


690

ADVERSE WEATHER


-

General: Do not use frozen materials or lay on frozen surfaces.


-

Air temperature requirements: Do not lay bricks/ blocks:



-

In cement gauged mortars when at or below 3°C and falling or unless it is at least 1°C and rising.



-

In hyd
raulic lime:sand mortars when at or below 5°C and falling or below 3°C and rising.



-

In thin joint mortar glue when outside the limits set by the mortar manufacturer.


-

Temperature of walling during curing: Above freezing until hardened.


-

Newly erecte
d walling: Protect at all times from:



-

Rain and snow.



-

Drying out too rapidly in hot conditions and in drying winds.





ADDITIONAL REQUIREMENTS FOR FACEWORK


740

FINISHED MASONRY WORK REFERENCE PANELS


-

General: Before proceeding with blockwork

on site, construct panels as specified. Give notice when
panels are dry.


-

Construct sample panel for cavity wall and internal partitions for approval to ensure that standard of
workmanship is acceptable, agreed standard of workmanship must be maintained
. Any masonry
panels not to the engineer or architects satisfaction must be taken down and re
-
built.


760

APPEARANCE


-

Brick/ block selection: Do not use units with damaged faces or arrises.


-

Quality control: Lay masonry units to match relevant refe
rence panels.



-

Setting out: To produce satisfactory junctions and joints with built
-
in elements and components.



-

Coursing: Evenly spaced using gauge rods.


-

Lifts: Complete in one operation.


-

Methods of protecting facework: Submit proposals.


780

GROUND LEVEL


-

Commencement of facework: Not less than 150 mm below finished level of adjoining ground or
external works level.


790

PUTLOG SCAFFOLDING


-

Use: Not permitted in facework.


800

TOOTHED BOND


-

Toothed bond not allowed without pr
ior approval. New and existing face
-
work in same plane: Bond
together at every course to achieve continuity.


830

CLEANLINESS


-

Facework: Keep clean.


-

Mortar on facework: Allow to dry before removing with stiff bristled brush.


-

Removal of marks a
nd stains: Rubbing not permitted.






25

G20

CARPENTRY/ TIMBER FRAMING/ FIRST FIXING




To be read with Preliminaries/ General conditions





GENERAL


150

STRENGTH GRADING OF TIMBER


-

Grader: Any company currently registered under a third party quality a
ssurance scheme operated by
a certification body approved by the UK Timber Grading Committee.


160

GRADING AND MARKING OF SOFTWOOD


-

Timber of a target/ finished thickness less than 100 mm and not specified for wet exposure: Graded
at an average moist
ure content not exceeding 20% with no reading being in excess of 24% and
clearly marked as ‘DRY’ or ‘KD’ (kiln dried).


-

Timber graded undried (green) and specified for installation at higher moisture contents: Clearly
marked as ‘WET’ or ‘GRN’. WET or GRN

timber must not be used without prior approval


-

Structural timber members cut from large graded sections: Re
-
graded to approval and marked
accordingly.





PRODUCTS


210

STRUCTURAL SOFTWOOD (GRADED DIRECT TO STRENGTH CLASS) FOR GENERAL
FRAMING AND
BATTENS TO RECEIVE CEDAR CLADDING


-

Grading standard: To BS 4978 or BS EN 519 or other national equivalent and so marked.


-

Strength class to BS EN 338: C16
/C22 to Engineers drawings

.


-

Treatment: pressure / vacuum treated with wood preservative, cut e
nds treated on site with brush
applied preservative.


310

STRUCTURAL PLYWOOD FOR GENERAL FRAMING / CARCASSING


-

Standard: To the relevant national standards and quality control procedures specified in BS 5268
-
2,
and so marked.


-

Marine Grade


-

Nomi
nal thickness/ number of plies: 19mm.


-

Finish: sanded.






WORKMANSHIP GENERALLY


401

CROSS SECTION DIMENSIONS OF STRUCTURAL SOFTWOOD AND HARDWOOD


-

Dimensions: Dimensions in this specification and shown on drawings are target sizes as defined in
B
S EN 336.


-

Tolerances: The tolerance indicators (T1) and (T2) specify the maximum permitted deviations from
target sizes as stated in



BS EN 336, clause 4.3:



-

Tolerance class 1 (T1) for sawn surfaces.



-

Tolerance class 2 (T2) for further processed

surfaces.


402

CROSS SECTION DIMENSIONS OF NONSTRUCTURAL SOFTWOOD


-

Dimensions: Dimensions in this specification and shown on drawings are finished sizes.


26


-

Maximum permitted deviations from finished sizes: As stated in BS EN 1313
-
1:



-

Clause 6 fo
r sawn sections.



-

Clause NA.2 for further processed sections.


403

CROSS SECTION DIMENSIONS OF NONSTRUCTURAL HARDWOOD


-

Dimensions: Dimensions in this specification and shown on drawings are finished sizes.


-

Maximum permitted deviations from fini
shed sizes: As stated in BS EN 1313
-
2:



-

Clause 6 for sawn sections.



-

Clause NA.3 for further processed sections.


420

WARPING OF TIMBER


-

Bow, spring, twist and cup: Not greater than the limits set down in BS 4978 or BS EN 519 for
softwood, or B
S 5756 for hardwood.


430

SELECTION AND USE OF TIMBER


-

Timber members damaged, crushed or split beyond the limits permitted by their grading: Do not
use.


-

Notches and holes: Position in relation to knots or other defects such that the strength of m
embers
will not be reduced.


-

Scarf joints, finger joints and splice plates: Do not use without approval.


440

PROCESSING TREATED TIMBER


-

Cutting and machining: As much as possible before treatment.


-

Extensively processed timber: Retreat timber sa
wn lengthways, thicknessed, planed, ploughed, etc.


-

Surfaces exposed by minor cutting and/ or drilling: Treat with two flood coats of a solution
recommended by main treatment solution manufacturer.


450

MOISTURE CONTENT


-

Moisture content of wood an
d wood based products at time of installation: Not more than:



-

Covered in generally unheated spaces:

24%.



-

Covered in generally heated spaces:


20%.



-

Internal in continuously heated spaces:

20%.


451

MOISTURE CONTENT TESTING


-

Pr
ocedure: When instructed, test timber sections with an approved electrical moisture meter.


-

Test sample: Test 5% but not less than 10 lengths of each cross
-
section in the centre of the length.


-

Test results: 90% of values obtained to be within the spec
ified range. Provide records of all tests.


510

PROTECTION


-

Generally: Keep timber dry and do not overstress, distort or disfigure sections or components during
transit, storage, lifting, erection or fixing.


-

Timber and components: Store under cove
r, clear of the ground and with good ventilation. Support
on regularly spaced, level bearers on a dry, firm base. Open pile to ensure free movement of air
through the stack.


-

Trussed rafters: Keep vertical during handling and storage.


520

EXPOSED EN
D GRAIN


-

Components: Seal exposed end grain before delivery to site:


530

PAINTED FINISHES


-

Structural timber to be painted: Primed as specified before delivery to site.


27


540

CLEAR FINISHES


-

Structural timber to be clear finished: Keep clean
and apply first coat of specified finish before
delivery to site.


550

EXPOSED TIMBER


-

Planed structural timber exposed to view in completed work: Prevent damage to and marking of
surfaces and arrises.






JOINTING TIMBER


570

JOINTING/ FIXING G
ENERALLY


-

Generally: Where not specified precisely, select methods of jointing and fixing and types, sizes and
spacings of fasteners in compliance with section Z20.


580

FRAMING ANCHORS


-

Manufacturer: HILTI / FISCHER / BAT / EXPAMET / CATNIC or eq
ual approved .


-

Material/ finish:galvanised / zinc plated.


-

Fasteners: Galvanized or sherardized square twist nails.


-

Size: Not less than size recommended by anchor manufacturer.



-

Fixing: Secure using not less than the number of nails recommended
by anchor manufacturer.


600

BLACK BOLTS AND NUTS


-

Standard: To BS EN ISO 898
-
1 and BS EN 20898
-
2.


-

Finish (applied by manufacturer):


610

BLACK CUP AND COUNTERSUNK HEAD BOLTS AND NUTS


-

Standard: To BS 4933.


-

Finish (applied by manufacture
r):.


620

WASHERS


-

Standard: Plain to BS 4320, spring to BS 4464.


-

Material and finish: To match bolts.


-

Dimensions when seated directly on timber surfaces: Unless specified otherwise:



-

Diameter/ side length: Not less than 3 times bolt diamete
r.



-

Thickness: Not less than 0.25 times bolt diameter.


625

STAINLESS STEEL BOLTS, NUTS AND WASHERS


-

Bolts and nuts:



-

Standard: To BS EN ISO 3506, Grade 4.6.


-

Washers:



-

Material: To match bolts.




630

BOLTED JOINTS


-

Bolt spacings (m
inimum): To BS 5268
-
2, table 81.


-

Holes for bolts: Located accurately and drilled to diameters as close as practical to the nominal bolt
diameter and not more than 2 mm larger.


28


-

Washers: Placed under bolt heads and nuts that would otherwise bear direct
ly on timber. Use spring
washers in locations which will be hidden or inaccessible in the completed building.


-

Bolt tightening: So that washers just bite the surface of the timber. Ensure that at least one complete
thread protrudes from the nut.


-

Check
ing: At agreed regular intervals up to Completion. Tighten as necessary.


670

ANTICORROSION FINISHES FOR FASTENERS


-

Galvanizing: To BS 7371
-
6, with internal threads tapped and lightly oiled following treatment.


-

Sherardizing: To BS 7371
-
8, Class 1.


-

Zinc plating: To BS EN ISO 4042 and passivated.





ERECTION AND INSTALLATION


721

EXPANSION ANCHORS


-

Manufacturer: HILTI / RAWL / FISCHER.



-

obtain engineers approval for all proposed fixings, and install in accordance to manufacturers
recomm
endations.


-

Material/ finish: anticorrosion to engineers approval


-

Spacing/ edge distance (minimum): to manufacturers recommendations.



-

Fixing not to be used if specified spacing or edge distance cannot be achieved, and alternative
fixing should be
obtained.


-

Installation holes: Drilled to diameter and depth recommended by manufacturer. Clean and free
from dust.


-

Installation/ tightening: To manufacturer’s instructions.



Expansion anchors not suitable in light weight blockwork.


725

HAMMER
-
I
N FASTENERS


-

Not suitable in light weight blockwork, only used in concrete subject to engineers approval.


740

PRE
-
ERECTION CHECKING


-

Timing: Not less than 10 days before proposed erection start date.


-

Checklist:



-

Foundations and other structu
res to which timber structure will be attached: Check for accuracy
of setting out.



-

Holding down bolts: Check for position, protruding length, condition and slackness.


-

Inaccuracies and defects: Report without delay.


-

Erection: Obtain permission to
commence.


750

MODIFICATIONS/ REPAIRS


-

Defects due to detailing or fabrication errors: Report without delay.


-

Methods of rectification: Obtain approval of proposals before starting modification or remedial
work.


-

Defective/ damaged components: Ti
mber members/ components may be rejected if the nature and/
or number of defects would result in an excessive amount of site repair.


760

TEMPORARY BRACING


-

Provision: As necessary to maintain structural timber components in position and to ensure
co
mplete stability during construction.




29

770

ADDITIONAL SUPPORTS


-

Provision: Position and fix additional studs, noggings and/ or battens to support edges of sheet
materials, and wall/ floor/ ceiling mounted appliances, fixtures, etc. shown on drawings
.


-

Material properties: Additional studs, noggings and battens to be of adequate size and have the same
treatment, if any, as adjacent timber supports.


775

BEARINGS


-

Timber surfaces which are to transmit loads: Finished to ensure close contact ove
r the whole of the
designed bearing area.


-

Packings: Where provided, to cover the whole of the designed bearing area.


-

Crushing strength: Not less than timber being supported.


-

In external locations: Rot and corrosion proof.


780

WALL PLATES


-

Position and alignment: To give the correct span and level for trusses, joists, etc.


-

Bedding: Fully in fresh mortar.


-

Joints: At corners and elsewhere where joints are unavoidable use nailed half lap joints. Do not use
short lengths of timber.


82
0

VERTICAL RESTRAINT STRAPS TYING WALLS TO ROOF FRAMING


-

Manufacturer: BAT or equal approved


-

Product reference: M305


-

Material/ finish: GALVANISED


-

Size:



-

Cross section: Not less than 30x5mm strap



-

Length: 1.0m long with 100mm turn down.


-

Centres: Not more than 1.2m


-

Fixing:



-

To roof members with not less than 2 no 12mm dia bolts .



-

To masonry with not less than 6 drilled and plugged screws evenly spaced, with at least one
screw located within 150 mm of the bottom end of each strap.


830

LATERAL RESTRAINT STRAPS TYING CEILINGS / ROOF / FLOORS INTO WALLS

-




Manufacturer: BAT or equal approved


-

Product reference: M305


-

Material/ finish: GALVANISED


-

Size:



-

Cross section: Not less than 30x5mm strap



-

Length: 1.0m long

with 100mm turn down.


-

Fixing: To soffit of purlins / rafters/ ties at not more than 1.2m m centres.


-

Ensure that cranked end is in tight contact with cavity face of wall

inner leaf and is not pointing
upwards.


-

Straps spanning purlins/ rafters/ tie
s running parallel to wall: Fix noggings and packs tightly beneath
straps.


-

Size of noggings and packs: Not less than three quarters of joist/ rafter/ tie depth and not less than
38 mm thick.


-

Notching: fix straps to soffit of roof members.


-

Fastene
rs: 12mm diameter bolts




30

850

INSPECTION GENERALLY


-

Structural timber
-
work: Give reasonable notice before covering up.


860

BOLTED JOINT INSPECTION


-

Timing: Inspect all accessible bolts at the end of the Defects Liability Period and tighten if
necessary.


870

ANCHOR TESTING


-

Standard: To BS 5080
-
1 and
-
2.


-

If anchor is used on site without prior approval and there are subsequent concerns with respect to its
acceptability, engineer / architect may request pullout (load test)


-

Test repo
rts: Submit as soon as available.




Q20

GRANULAR SUB
-
BASES TO ROADS/ PAVINGS




To be read with Preliminaries/ General conditions.



120

CHECKING CALIFORNIA BEARING RATIO (CBR) OF SUBGRADES


-

Subgrade variation: If material appears to vary from that
stated in the site investigation report, or if
there are extensive soft spots, test subgrade CBR to BS 1377
-
4 or BS 1377
-
9. Submit results and
obtain instructions before proceeding.


130

HERBICIDES


-

Type: translocated non residual herbicide to engine
ers approval .


-

Application: To all subgrade formations prior to laying.


140

EXCAVATION OF SUBGRADES


-

Final excavation to formation or sub
-
formation level: Carry out immediately before compaction of
subgrade.


-

Soft spots and voids: Give notice.


-

Wet conditions: Do not excavate or compact when the subgrade may be damaged or destabilized.


145

PREPARATION AND COMPACTION OF SUBGRADES


-

Timing: Immediately before placing sub
-
base.


-

Soft or damaged areas: agree course of action with engineer,

with respect to dewatering /
excavation, or provision of capping layer.


-

Compaction: Thoroughly, by roller or other suitable means, adequate to resist subsidence or
deformation of the subgrade during construction and of the completed roads/ pavings when

in use.
Take particular care to compact fully at intrusions, perimeters and where local excavation and
backfilling has taken place.


150

SUBGRADES FOR VEHICULAR AREAS


-

Preparation and treatment: To Highways Agency ‘Specification for highway works’,
clauses 616
and 617.


170

GEOTEXTILE FILTER/ SEPARATOR MEMBRANES (not envisaged that there will be
requirement on this scheme)


-

Manufacturer: Du Pont, Exxon, Netlon / Tensar International or other equal a
pproved.


31


-

Product reference: Terram / Typar

HR geotextile / Tensar SS30 geogrid or equal approved .


-

Jointing: overlap in accordance with manufacturers recommendations.


-

Protected from:



-

Exposure to light, except during laying (maximum five hours).



-

Contaminants.



-

Materials listed as
potentially deleterious by geotextile manufacturer.



-

Damage, until fully covered by fill.



-

Wind uplift, by laying not more than 15 m before covering with fill.


-

Preparation: Humps and sharp projections removed and hollows filled before laying.


200

SUBGRADE IMPROVEMENT LAYER (CAPPING)


-

Material: To Highways Agency ‘Specification for highway works’, table 6/1, Class 6F1, 6F2 or
6F3.


-

Standard: Placed and compacted to Highways Agency ‘Specification for highway works’, table 6/1,
clauses 612 an
d 613.3, 613.8, 613.9, 613.10 and 613.13.


205

HIGHWAYS AGENCY TYPE 2 GRANULAR MATERIAL


-

Material: Type 2 unbound mixture to Highways Agency ‘Specification for highway works’, clause
801.


210

HIGHWAYS AGENCY TYPE 1 GRANULAR MATERIAL


-

Material
: Type 1 unbound mixture to Highways Agency ‘Specification for highway works’, clause
801.





211

GRANULAR MATERIAL


-

Quality: Free from excessive dust, well graded, all pieces less than 75 mm in any direction,
minimum 10% fines value of 50 kN when t
ested in a soaked condition to BS 812
-
111 and BS EN
1097
-
2, and in any one layer only one of the following:



-

Crushed rock (other than argillaceous rock) or quarry waste with not more binding material than
is required to help hold the stone together.



-

Crushed concrete, crushed brick or tile, free from plaster, timber and metal.



-

Gravel or hoggin with not more clay content than is required to bind the material together, and
with no large lumps of clay.



-

Natural gravel.



-

Natural sand.


-

Filling
: Spread and levelled in 150 mm maximum layers, each layer thoroughly compacted.


215

GRANULAR MATERIAL FOR PERMEABLE PAVING


-

Material: clean broken stone.


-

Grading: 65mm maximum size crusher run.


-

Laying: 150mm layer rolled and compacted.


2
20

FROST SUSCEPTIBLE GRANULAR MATERIAL


-

Definition (non frost susceptible material): To Highways Agency 'Specification for highway works'
clause 801.8.


-

Frost susceptible material not permitted .


-

Testing: Test materials used if required and supply c
ertificates.


225

PLACING OF MATERIAL WITH HIGH SULFATE CONTENT


-

Standard: To Highways Agency ‘Specification for highway works’, clauses 801.2 and 801.3.


32



-

Material with high sulphate content not permitted .


230

PLACING GRANULAR MATERIAL GENER
ALLY


-

Preparation: Loose soil, rubbish and standing water removed.


-

Structures, membranes and buried services: Ensure stability and avoid damage.


240

LAYING GRANULAR SUB
-
BASES FOR VEHICULAR AREAS


-

General: Spread and levelled in layers. As soon
as possible thereafter compact each layer.


-

Standard: To Highways Agency ‘Specification for highway works’ clause 802.


-

At drainage fittings, inspection covers, perimeters and where local excavation and backfilling has
taken place: Take particular care

to compact fully.


241

LAYING GRANULAR SUB
-
BASES FOR VEHICULAR AREAS


-

Proposals: Well in advance of starting work submit details of:



-

Maximum depth of each compacted layer.



-

Type of plant.



-

Minimum number of passes per layer.


-

General: S
pread and levelled in layers. As soon as possible thereafter compact each layer.


-

At drainage fittings, inspection covers, perimeters and where local excavation and backfilling has
taken place: Take particular care to compact fully.


-

Sub
-
base surface a
fter compaction and immediately before overlaying: Uniformly well closed and
free from loose material, cracks, ruts or hollows.


250

LAYING GRANULAR SUB
-
BASES FOR PAVEMENTS PLAY AREAS.


-

General: Spread and levelled.


-

Compaction:



-

Timing: As so
on as possible after laying.



-

Method: By roller or other suitable means, adequate to resist subsidence or deformation of the
sub
-
base during construction and of the completed paving when in use. Take particular care to
compact fully at intrusions, perim
eters and where local excavation and backfilling has taken
place.


310

ACCURACY


-

Permissible deviation from required levels, falls and cambers (maximum):



-

Subgrades:




Roads and parking areas: +20
-
30 mm.




Footways and recreation areas: ± 20 m
m.



-

Sub
-
bases:




Roads and parking areas: ± 20 mm.




Footways and recreation areas: ± 20 mm.


315

ACCURACY FOR SUB
-
BASES TO SPORTS SURFACING


-

Profile: Lay sub
-
base to levels shown on drawings.


-

Maximum gradient in any direction: 1:80.


-

Surfa
ce regularity: As specified by clause 310.


-

Deviation from finished plane: +/
-

20mm.


-

General accuracy: Sufficient to ensure that the surface will not cause a hazard or a ball to deflect
from its true path.





33

320

BLINDING


-

Locations: Surfaces to

receive sand bedded interlocking brick or block paving to sections Q24 and
Q25.


-

Material: Sand, fine gravel or PFA.


-

Finish: Close, smooth, compacted surface.


330

COLD WEATHER WORKING


-

Frozen materials: Do not use.


-

Freezing conditions: Do n
ot place fill on frozen surfaces. Remove material affected by frost.
Replace and recompact if not damaged after thawing.


340

PROTECTION


-

Sub
-
bases: As soon as practicable, cover with subsequent layers, specified elsewhere.


-

Subgrades and sub
-
bases
: Prevent degradation by construction traffic, construction operations and
inclement weather.



Q22

COATED MACADAM/ ASPHALT ROADS/ PAVINGS




To be read with Preliminaries/ General conditions.





TYPES OF PAVING


110

COATED MACADAM PAVING FOR GENERAL
FOOTPATH CONSTRUCTION


-

Materials and workmanship: To Highways Agency (HA) ‘Specification for highway works’.


-

Granular sub
-
base: 65mm maximum size well graded crusher run.



-

Thickness: 150mm


-

Subgrade improvement layer: 65mm max. size well graded

crusher run.



-

Thickness: 225mm.


-

Base Course: 20mm nominal size Dense bitumen macadam to B.S. 4987:1993 / HA clause 903.



-

Thickness: 50mm.

.

-

Surface course: 14mm nominal size bitumen macadam to B.S. 4987: 1993



-

Thickness: 25mm.


115

COAT
ED MACADAM PAVING FOR HARD PLAY AREAS


-

Materials and workmanship: To Highways Agency (HA) ‘Specification for highway works’.


-

Granular sub
-
base: 110mm maximum size well graded crusher run.



-

Thickness: 225mm


-

Granular Base: 65mm max. size well gra
ded crusher run.



-

Thickness: 150mm.


-

Base Course: 20mm nominal size Dense bitumen macadam to B.S. 4987:1993 / HA clause 903.



-

Thickness: 60mm.

.

-

Surface course: 14mm nominal size bitumen macadam to B.S. 4987: 1993



-

Thickness: 40mm.


140

R
OLLED ASPHALT PAVING FOR VEHICULAR ACCESS AND CAR PARKING AREAS


-

Materials and workmanship: To Highways Agency (HA) ‘Specification for highway works’.


-

Granular sub
-
base: 65mm maximum guage crusher run.



-

Thickness: 225mm.


-

Granular Base: 65mm maxi
mum guage crusher run.


34



-

Thickness: 150mm .


-

Base Course: 20mm nominal size bitumen macadam to B.S. 4987:1993



-

Thickness: 60mm.


-

Surface course:Hot rolled asphalt to B.S. 594 1992. 30% course aggregate to table 6, column 6/4,
schedule 1B .



-

Thi
ckness: 40mm.





PREPARATORY WORK/ REQUIREMENTS


220

BITUMINOUS MATERIALS GENERALLY


-

Suppliers’ names: Submit.


-

Timing (minimum): 2 weeks before starting work.


-

Test certificates: At the time of delivery for each manufacturing batch submit certi
ficate:



-

Confirming compliance with this specification and the relevant British Standard.



-

Stating full details of composition of mix.


230

SAMPLES


-

Submit: to CA for approval


240

ACCEPTANCE OF SUB
-
BASE


-

Surface: Sound, clean and suitabl
y close textured.


-

Levels and falls: To be within the specified tolerances:



-

Vehicular areas: +10 to
-
30 mm.



-

Pedestrian areas: ±12 mm.



-

Drainage outlets: 0 to
-
10 mm of the required finished level.


-

Kerbs and edgings: Complete, adequately bed
ded and haunched and to the required levels.


250

ABUTMENTS


-

Edges of manholes, kerbs and other abutments: Clean and paint with a thin uniform coating of
bituminous tack coat.





LAYING


310

LAYING GENERALLY


-

Preparation: Remove all loose mate
rial, rubbish and standing water.


-

Adjacent work: Form neat junctions. Do not damage.


-

Channels, kerbs, inspection covers etc: Keep clean.


-

New paving:



-

Keep traffic free until it has cooled to prevailing atmospheric temperature.



-

Do not allow

rollers to stand at any time.



-

Prevent damage.



-

Lines and levels: With regular falls to prevent ponding.



-

Overall texture: Smooth, even and free from dragging, tearing or segregation.



-

State on completion: Clean.


320

ADVERSE WEATHER


-

Frozen materials: Do not use.


-

Suspend laying:



-

During freezing conditions.


35



-

If the air temperature reaches 0°C, or in calm dry conditions
-
3°C, on a falling thermometer.



-

Hot rolled asphalt: During periods of continuous or heavy rain.


330

LEVELS


-

Permissible deviation from the required levels, falls and cambers (maximum):



-

Finished surface: ±6 mm.



-

Adjacent to gullies and manholes: 0 to +3 mm.


340

FLATNESS/ SURFACE REGULARITY


-

Deviation of surface: Where appropriate in relati
on to the geometry of the surface, the variation in
gap under a 3 m straightedge placed anywhere on the surface to be not more than:



-

Base: +/
-

50mm.



-

Binder course: +/
-

25mm .



-

Surface course: +/
-

10mm .



-

Where a straightedge cannot be used th
e surface must be of a comparable standard of accuracy
when judged by eye.


350

CONTRACTOR’S USE OF PAVEMENTS


-

Before use: Fill interstices of open
-
grained surface with coated grit to BS 4987
-
1, tables 34
-
36 with
soluble bitumen content for all aggre
gates in the range of 1.5
-
3.5%. Remove surplus. Apply binder
and chippings as clause 360.


-

Final surfacing:



-

Timing: Defer laying until as late as practicable.



-

Immediately before laying final surfacing: Clean and make good the base/ binder course.

Allow
to dry. Uniformly apply, without puddles, a tack coat of sprayed bitumen emulsion of a suitable
grade to BS 434
-
1 at 1.5
-
2.0 kg/m². Allow emulsion to break completely before applying
surfacing.


351

CONTRACTOR’S USE OF PAVEMENTS


-

Final surfaci
ng:



-

Timing: Defer laying until as late as practicable.



-

Immediately before laying final surfacing: Clean and make good the base/ binder course. Allow
to dry. Uniformly apply, without puddles, a tack coat of sprayed bitumen emulsion of a suitable
gra
de to BS 434
-
1 at 1.5
-
2.0 kg/m². Allow emulsion to break completely before applying
surfacing.



Z21

MORTARS




To be read with Preliminaries/ General conditions.




CEMENT GAUGED MORTARS


110

CEMENT GAUGED MORTAR MIXES


-

Specification: Proportions an
d additional requirements for mortar materials are specified elsewhere.


120

SAND FOR SITE MADE CEMENT GAUGED MASONRY MORTARS


-

Standard: To BS EN 13139.


-

Grading: 0/2 (FP or MP).


-

Fines content where the proportion of sand in a mortar mix is spec
ified as a range (e.g. 1:1: 5
-
6):




Lower proportion of sand: Use category 3 fines.


36




Higher proportion of sand: Use category 2 fines.


-

Sand for facework mortar: Maintain consistent colour and texture. Obtain from one source.


131

READY
-
MIXED LIME/

SAND FOR CEMENT GAUGED MASONRY MORTARS


-

Standard: To BS 4721 or BS EN 998
-
2.


-

Lime: Nonhydraulic to BS EN 459
-
1.



-

Type: CL 90S.


-

Pigments for coloured mortars: To BS EN 12878.


135

SITE MADE LIME/ SAND FOR CEMENT GAUGED MASONRY MORTARS


-

Per
mitted use: Where a special colour is not required and in lieu of factory made ready
-
mixed
material.


-

Lime: Nonhydraulic to BS EN 459
-
1.



-

Type: CL 90S.


-

Mixing: Thoroughly mix lime with sand, in the dry state. Add water and mix again. Allow to stand
,
without drying out, for at least 16 hours before using.


160

CEMENTS FOR MORTARS


-

Cement: To BS EN 197
-
1 and CE marked.



-

Types:

Portland cement, CEM I.



-

Strength class: 32.5, 42.5 or 52.5.


-

White cement: To BS EN 197
-
1 and CE marked.



-

Ty
pe: Portland cement, CEM I.



-

Strength class: 52.5.


-

Sulfate resisting cement: To BS 4027 and Kitemarked.



-

Strength class: 42.5.


-

Masonry cement: To BS 5224 and Kitemarked.



-

Class: MC 12.5 (with air entraining agent).


180

ADMIXTURES FOR SI
TE MADE CEMENT GAUGED MORTARS


-

Air entraining (plasticizing) admixtures: To BS 4887
-
1 and compatible with other mortar
constituents.


-

Other admixtures: Submit proposals.


-

Prohibited admixtures: Calcium chloride and any admixture containing calcium ch
loride.


190

RETARDED READY TO USE CEMENT GAUGED MASONRY MORTARS


-

Standard: To BS 4721 or BS EN 998
-
2.


-

NOT PERMITTED


200

STORAGE OF CEMENT GAUGED MORTAR MATERIALS


-

Sands and aggregates: Keep different types/ grades in separate stockpiles on

hard, clean, free
-
draining bases.


-

Factory made ready
-
mixed lime:sand/ ready to use mortars: Keep in covered containers to prevent
drying out or wetting.


-

Bagged cement/ hydrated lime: Store off the ground in dry conditions.


210

MAKING CEMENT GAU
GED MORTARS


-

Batching: By volume. Use clean and accurate gauge boxes or buckets.



-

Mix proportions: Based on dry sand. Allow for bulking of damp sand.


-

Mixing: Mix materials thoroughly to uniform consistency, free from lumps.



-

Mortars containing a
ir entraining admixtures: Mix mechanically. Do not overmix.


37


-

Working time (maximum): Two hours at normal temperatures


-

Contamination: Prevent intermixing with other materials.









38

G10

STRUCTURAL STEEL FRAMING




To be read with Preliminaries/ Gener
al conditions.





GENERAL REQUIREMENTS/ INFORMATION


110

DESIGN OF STEELWORK SUPPORTI
NG MAIN ROOF,CANOPY ,FLOORS, WALLS and
FRAMING GLAZED AREAS.


-

Design concep
t: Roof beams,floor beams to be supported on loadbearing structure.
Glazed areas as per E
ngineers drawings.


-

Design standard: The structural steelwork has been designed to BS 5950, where
applicable.


-

Supplementary requirements: National Structural Steelwork Specification for Building
Construction 4
th

editon applies..


-

Completion of desi
gn: Design and detail connections to BS 5950.


-

Loading requirements: member calculations / loadings / end reactions supplied by
engineer upon request..


-

Fixings to foundations/ walls: rafters to be fixed in position on padstones using 2 no. M16
HILTI
HIT HY150 resin fixings or equal approved. Padstones / ring beams strapped to wall
using 2 no. M305 STRAPS..

Posts to be fixed in position on padstones using 4 no.
M16/M20 HILTI HIT HY150 resin fixings or equal approved.


116

DESIGN CONSTRAINTS


EXTER
NALLY EXPOSED STEELWORK IF REQUIRED TO
BE GALVANIZED


-

Steel grades:(S275) Do not use steel downgraded from a higher specification.


-

Detail design: Avoid details that will increase the risk of initiating liquid metal assisted
cracking (LMAC).


120

D
RAWINGS AND CALCULATIONS


-

Requirement: Before preparing detailed fabrication drawings, submit:



-

General arrangement drawings with individual steel members clearly identified.



-

Calculations for major connections.


125

SPECIFICATION STANDARD


-

S
tandard: Comply with latest edition of National Structural S
teelwork Specification (NSSS).
5
TH

EDITION


-

Additional requirements: provide shop drawings for approval prior to fabrication allowing 1
day per drawing.


-

Document availability: For the duratio
n of the work, at fabrication shop and on site.


130

GENERAL STEEL SECTIONS AND PLATES


-

Standard: to comply with BS EN 10025 & EN 10113


-

Grade: S275



-

Options: sections to BS 4


-

Source: Obtain steel from a source accredited to a national or in
ternationally accepted
quality standard.



135

HOLLOW STEEL SECTIONS


-

Standard: BS EN 10025 & EN 10113 .


-

Grade: S275


39



-

Options: HOT ROLLED SECTIONS MUST BE USED, COLD FORMED NOT
PERMITTED .


-

Source: Obtain steel from a source accredited to a
national or internationally accepted
quality standard.






FABRICATION


180

NOTIFICATION OF COMMENCEMENT


-

Give notice: Before fabrication is due to start.



-

Period of notice (minimum): 1 day


190

MARKING


-

Identifying and recording materials
and components: Submit details of proposed methods.


-

Location of marks:



-

Generally: Visible for checking after erection.



-

Weathering steel: On surfaces not exposed to open view in the completed work.


-

Steel to be blast cleaned, pickled, metal spr
ayed or galvanized: Marked so that
subsequent treatment cannot obliterate the marking.


195

HARD STAMPING


-

Usage: Not permitted except as indicated on drawings.


200

FAYING SURFACES FOR HIGH
-
STRENGTH FRICTION GRIP (HSFG) JOINTS


-

Steel 25 mm thi
ck or over: Check faying surfaces for deformities that may reduce slip
factor to below design limit.


-

Remedial measures: Submit proposals.


210

END CONNECTIONS


-

Angle web cleats: Project 10 mm beyond ends of simply supported members.


215

HOLLO
W SECTIONS


-

Insides of sections: Debris and moisture removed before sealing ends and openings.


225

STEELWORK TO BE GALVANIZED


-

Cutting, drilling and shop welding: Complete before galvanizing.


-

Vent and drain holes: Provide as necessary.


-

Locat
ions: Submit proposals.





235

SHOP INSPECTION


-

Give notice: Before fabricating 2 working days



-

Period of notice (minimum): 2 days





WELDING


255

SITE WELDING


-

Usage: Approval must be sought from engineer, generally not permitted


-

Work
ing conditions: Suitable and safe. Do not weld when surfaces are wet or when
ambient temperature is below 0°C.


40


270

ADDITIONAL WELDS


-

Welds (including tack welds) not indicated on drawings: Not permitted without approval.


290

FINISHED WELDS


-

F
inished welds: Carefully dressed to remove slag without deforming surface of weld.





BOLT ASSEMBLIES


305

PROPRIETARY ANCHORS


-

Manufacturer: HILTI / RAWL / FISCHER or equal approved .


-

Product reference: proposals to be forwarded to engineer by
steel fabricator for approval.


-

Anchor type: HILTI HRD
-
U14/
-
S frame anchor


-

Material: Stainless Steel


310

ANCHORAGES TO CONCRETE


-

Design standard: To ETAG 001, Annex C.


-

Anchor type:designed by steel fabricator to engineers approval



specific
ation to be forwarded for approval .


-

Material: stainless steel with neoprene isolating sleeve or galvanised steel



-

Coating applied by manufacturer: minimum 5 um


-

Concrete:



-

Grade: C28/35 .



-

Condition: sound uncracked.


-

Characteristic resist
ances of single anchor remote from edge of concrete (minimum):



-

Tension: loadings to be obtained from engineer for relevant fixings.



-

Shear:

loadings to be obtained from engineer for relevant fixings.


-

Use HILTI HIT
-
HY 150 injection mortar with M20

HAS rod or equal approved.


315

HOLDING DOWN SYSTEMS


-

Bolts:



-

Standard:



-

Type: mild steel.



-

Grade: 4.6.



-

Diameter: 20mm .


-

Bolt boxes: designed and supplied by steel fabricator for installation by main contractor.


-

Anchorage: bottom

washers.


335

SPRING WASHERS


-

Standard: To BS 4464.


370

GALVANIZED COATING TO BOLT ASSEMBLIES


-

Standard: To BS 7371
-
6.


-

Galvanizing: Applied by fastener manufacturer. Passivated and lubricated if no additional
coatings are specified. Nuts t
apped after galvanizing.


380

ZINC PLATED FINISH TO BOLT ASSEMBLIES


-

Standard: To BS 7371
-
3 or BS EN ISO 4042.


-

Zinc plating: Applied by fastener manufacturer. Clear passivated if no additional coatings
are specified. Nuts tapped after plating.


41


-

Use/ location: to be used on majority of steelwork connections.


390

SEALED HOLLOW SECTIONS


-

Bolt holes: Sealed to prevent access of moisture.



-

Method of sealing: neoprene washer / sleeve.





ERECTION


405

OUTLINE METHOD OF ERECTION


-

Provid
e erection method statement for approval prior to commencement.


410

PRE
-
ERECTION CHECKS


-

Scope: At least 7 days before proposed erection start date, check the following:



-

Foundations and other structures to which steelwork will be attached: Accur
acy of
setting out.



-

Holding down bolts: Position, protruding length, slackness and condition.


-

Inaccuracies and defects: Report without delay.


-

Permission to commence erection: Obtain.


420

SETTING OUT


-

Permissible deviations to the requireme
nts of the NSSS, comply with the following:





425

MODIFICATIONS


-

Steelwork: Do not modify design or stellwork on site without approval.


-

Temporary fabrication/ erection attachments: steelwork subcontractor to provide whatever
temporary guying or
bracing is necessary until adequate permanent support has been
installed by the main contractor.


432

TEMPORARY SUPPORT


-

Bracing/ Restraints: Provide as necessary until permanent support is achieved. .



440

COLUMN BASES


-

Levels: Adjust using s
teel shims or folding wedges no larger than necessary.


-

Location of shims/ wedges: Position symmetrically around perimeter of base plate. Do not
use a single central pack.


-

Give notice: If space beneath any column base is outside specified limits for b
edding
thickness.


-

Accuracy of erection: Check, and correct errors before filling and bedding beneath bases
and carrying out other adjacent work.


441

MORTAR FILLING/ BEDDING OF COLUMN BASES


-

Bedding thickness range: 25


50mm.


-

Bolt pockets: Com
pletely filled with neat cement slurry.


-

Spaces beneath base plates: Completely filled as follows:



-

Spaces 0
-
25 mm deep: Obtain instructions.



-

Spaces 25
-
50 mm deep: 1:1 cement:sand mortar, just fluid enough to pour. Tamped
well as filling proceeds.

Provide temporary shuttering as necessary.



-

Spaces 50
-
80 mm deep: 1:2 cement:sand mortar, just damp, tamped well against
properly fixed supports as filling proceeds.


42


-

Cement: Portland cement BS EN 197
-
1
-

CEM I 42.5 or 52.5.


-

Sand: To BS EN 12620,
grade 0/4 or 0/2 (MP).



445

MOVEMENT JOINTS


-

Sliding surfaces: Coated with molybdenum disulfide grease before connecting.


-

Appearance and fit: Bolts centred in slotted holes. Joints free to move. Slotted holes
provided in rafter bearing plates to
receive centrally located fixing bolts to accommodate
thermal movements in steel.


447

BONDED ANCHORS


-

Holes: Clean and free from dust at time of installing anchor.


-

Permeable sleeves: Use in conditions where otherwise the loss of bonding agent wou
ld be
unacceptably high.





TESTING


465

TESTING


-

Testing: Arrange the following tests. Prepare test pieces as necessary.


-

Test: paint thickness, weld quality etc may be tested on site in accordance with relevant
standards such as National Structu
ral Steelwork Specification.


470

SITE TESTING OF ANCHORS TO MASONRY


-

Standard: To BS 5080.


-

Testing will be required in event of engineer / clerk of works suspecting that anchors are
not installed in accordance with manufacturers recommendations.


-

Test results: Report failures and seek instructions.


475

PRODUCTS


-

Steel: Submit test certificates.





PROTECTIVE COATINGS


523

COMPATIBILITY OF SHOP PRIMER WITH SITE APPLIED INTUMESCENT COATING


-

Intumescent coating: M61/ (intumscent coat
ing not specified, however fabricator must
provide written confirmation that their proposed shop primers are compatible with one or
more intumescent coatings, giving details of respective coating.)


-

Primer: Compatible with coating under general and fire
conditions.


-

Manufacturer's recommendations and test evidence: Submit before priming. Include fire
test data to BS 476
-
20 and
-
21, or BS EN 1363
-
1 and BS EN 1365
-
2,
-
3, and/ or
-
4 as
appropriate.


535

INSPECTION OF COATING WORK


-

Work in progress: P
ermit coating manufacturer to inspect and take samples of products.


-

Notice: Give notice of dates for:



-

Start of surface preparation and coating.



-

Coated members or components leaving the works.



-

Period of notice (minimum): 5 working days.




43

550

INSPECTION AND TESTING FOR LIQUID METAL ASSISTED CRACKING (LMAC)


-

Visual inspection: Inspect galvanized surfaces for cracks or indications of LMAC cracking.



-

Extent: limited amount of steel exposed externally and galvanised as a consequence.



-

Timing: Before erection of steelwork or application of other coatings.



-

Inspector: Submit, on request, evidence of training and competence in visual inspection
for LMAC.


-

Sites of suspected defects: Remove zinc coating by grinding back to bright meta
l for a
distance of not less than 50 mm around each defect and from a similar area on opposite
face of member.


-

Non
-
destructive testing:



-

Test locations: Areas where LMAC is suspected following visual inspection, and
corresponding areas of members wit
h similar detailing.


-

Inspection and test reports: Submit as soon as available.


-

Repairs and recoating: Submit proposals.





PROTECTIVE COATING SYSTEMS


620

GALVANIZING TO BLAST CLEANED STEEL


-

Use/ location: External posts and beams over areas s
uch as covered play area .


-

Preparation: Blast cleaning to BS EN ISO 8501
-
1, preparation grade Sa2½ using chilled
angular iron grit grade G24 to give a coarse surface profile, followed by chemical cleaning.


-

Galvanizing: To BS EN ISO 1461.



-

Minimum
mean coating thickness: 140 micrometres.


630

GALVANIZING PLUS SITE APPLIED Polyurethane finish to Architects Specification


-

Use/ location: External / exposed posts beams to covered play area etc..


-

Shop preparation: shot blast and galvanise in acc
ordance with clause 620.


-

Acid etch. .


-

Apply zinc phosphate Epoxy sealer coat


50 um.


-

Apply high build Epoxy M.I.O.


100um


-

Site applied re
-
coatable polyurethane finish


60 um


638

SHOP PRIMING FOR GENERAL STRUCTURAL MEMBERS


-

Use/ locat
ion: roof structure


-

Shop preparation: Blast cleaning to BS EN ISO 8501
-
1, preparation grade Sa 2.5.


-

Primer: high build zinc phosphate primer.


-

Dry film thickness: 75um.


-

Special requirements: touch up any damaged areas with brush applied high bui
ld primer
on site immediately after erection.





PREPARATION FOR PAINTING


710

OFFSITE PREPARATION AND PAINTING


-

Working area: Covered and properly lit, heated and ventilated.


-

Sequence of working:


-

Fabricate, blast clean, prime.


-

Surfaces in
accessible after assembly: Apply full treatment and coating system including, if
necessary, local application of site coatings.



44

725

MANUAL CLEANING OF NEW STEELWORK


-

Preparation: Remove fins, burrs, sharp edges, weld spatter, loose rust and loose sc
ale.


-

Surface finish: Clean but unpolished to BS EN ISO 8501
-
1, grade St 2.


-

Finishing: Thoroughly degrease and clean down. Remove any consequent rusting back to
grade St 2. Prime without delay.


730

PREPARATION FOR SITE WELDING OF SHOP PAINTED STE
ELWORK


-

Method: Select from the following:



-

Mask weld areas immediately after blast cleaning and before coating steelwork. If paint
system comprises more than one coat, step each coat 30 mm back from edge of
preceding coat and away from masked areas.
Remove masking immediately before
welding.



-

Prepare and paint steelwork including weld areas. Grind off to bare steel around each
weld area immediately before welding.


735

TREATMENT OF SITE WELDED JOINTS IN PAINTED STEELWORK


-

Preparation: After w
elding, and without delay, remove scale and weld spatter from weld
areas. Remove traces of rust. Wash with clean water and allow to dry. Prime without delay.


-

Protective/ Decorative coatings: Apply to weld areas to match surrounding painted areas.


7
36

TREATMENT OF SITE WELDED JOINTS IN GALVANIZED STEELWORK


-

Preparation: After welding, and without delay, remove scale and weld spatter from weld
areas. Remove traces of rust. Wash with clean water and allow to dry.


-

Coating: Reinstate using one of th
e methods given in BS EN ISO 1461, clause 6.3.


740

BOLTED JOINTS (OTHER THAN FRICTION GRIP JOINTS)


-

Steelwork to be shop painted: Apply full shop specification to joint faces.


-

Steelwork to be erected with mill finish then site painted: Before ere
ction, prepare and
prime joint faces and allow to dry.


-

Bolted joints in externally exposed steelwork:



-

Immediately before assembling, apply a further coat of primer and bring surfaces
together while still wet.



-

After assembling and before applying

site coatings, seal crevices to bolts and joint
perimeters with a compatible sealant.


745

FAYING SURFACES OF FRICTION GRIP JOINTS


-

Protection: Immediately after blast cleaning and before coating surrounding areas, mask
faying surfaces to protect fr
om contamination and deterioration.



-

Paint systems comprising more than one coat: Step each coat 30 mm back from edge
of preceding coat and away from masked areas.


-

Removal of protection: Immediately before bolting, remove masking. Check faying
surfac
es are free from adhesive. Clean with solvent if necessary.


750

FRICTION GRIP JOINTS IN SHOP PAINTED STEELWORK


-

Post assembly treatment of bolts and surrounding areas: After final tightening of bolts and
inspection of joints:



-

Thoroughly degrease

and clean uncoated areas including bolts.



-

Prime without delay.



-

Apply full shop coating specification.


-

Direct tension indicators: Seal measuring gap to prevent ingress of moisture.



45

755

UNCOATED FASTENERS


-

Treatment: After steelwork erecti
on and before applying site coatings, thoroughly degrease
and clean. Without delay, coat to match adjacent shop painted areas.


760

GALVANIZED FASTENERS


-

Treatment: After steelwork erection and before applying site coatings, thoroughly degrease
and c
lean. Etch prime.


765

SITE PREPARATION OF SHOP PAINTED STEELWORK


-

Preparation: Touch in shop coats, as necessary, and allow to dry. Before applying site
coats (when specified), abrade surfaces or wash down or both, as recommended by paint
manufactur
er.


770

SITE PREPARATION OF GALVANIZED SURFACES FOR PAINTING


-

Preparation: Thoroughly degrease. Remove white corrosion products. Wash off and allow
to dry before applying etching wash or primer.





PAINTING


810

ENVIRONMENTAL CONDITIONS


-

Gene
ral requirements prior to starting coating work:



-

Surfaces: Unaffected by moisture or frost.



-

Steel temperature: At least 3°C above dew point, with conditions stable or improving,
and not high enough to cause blistering or wrinkling of the coating.



-

Relative humidity: Below 85%.


815

COATINGS


-

Surfaces to be coated: Clean, dust free and suitably dry. Previous coats to be adequately
cured.


-

Multiple coats of same material: Use different tints to assist checking of complete
coverage.


-

Penul
timate coat: Colour recommended by paint manufacturer to suit top coat colour.


-

Finish required: Smooth and even, of uniform thickness and colour, free from defects.


820

FILM THICKNESS


-

Wet film thickness: During application, check thickness of ea
ch coat with a wheel or comb
gauge used in accordance with BS EN ISO 2808.


-

Accumulated dry film thickness: After each coat has dried, check total accumulated film
thickness.



-

Method: Magnetic or electromagnetic meter.



-

Number and position of measu
rements: As directed.



-

Validation: Measurements to be independently witnessed.



-

Meter calibration: Check against standard shims and recalibrate regularly against a
smooth steel reference plate.


-

Average dry film thickness:



-

At least specified t
hickness over any square metre.



-

No reading to be less than 75% of specified thickness.


-

Top coat dry film thickness: Sufficient to give an even, solid, opaque appearance.




46

825

STRIPE COAT


-

External angles, nuts, bolt heads, rough weld seams, a
nd areas difficult to coat: Apply an
additional stripe coat of high build zinc phosphate primer.


850

JUNCTIONS WITH CONCRETE


-

Exposed steelwork partially embedded or encased in concrete: Apply two coats of
bituminous coating locally to the steel/con
crete junction.