Draw wall sections and

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25 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Competency: 206.00

Draw wall sections and
details.

Objective: 206.02

Apply concepts of wood sill and floor
construction.

Lumber sizes

Nominal sizes

2 x 4

2 x 6

2 x 8

2 x 10

2 x 12

Actual sizes

1 ½ x 3 ½

1 ½ x 5 ½

1 ½ x 7 ½

1 ½ x 9 ¼

1 ½ x 11 ¼



Common lengths

8’, 10’, 12’, 14’, 16’

Sill


Structurally graded according to knots
(size, tightness, placement), wane, and
straightness


Must be pressure
-
treated lumber


Used as a transition between masonry and
standard lumber


Anchor bolts embedded into masonry are
commonly used to tie the sill to the foundation


Nails can be shot into concrete with a low
-
caliber nail gun

Joists


Provide support for floor


Wood or steel

Joists


Size of wood joists depends upon


Species of lumber


Wood grade


Spacing


12”, 16”, or 24” O.C. spacing is most
common


Works with the 48” module common to
plywood and OSB


Joists


Recommended live load (40psf)


Distance between supports (clear span)


Joists manufacturer’s charts


Joists


Double joists must be provided under walls
running parallel to the joist direction


May be solid or built up of two joists


May be solid or built up of two joists

Joists


Bridging


May be used between joists


Transfers the floor loads to adjacent joists


Stiffens joists


Aligns joists vertically


May be diagonal wood members, metal or 1x3
wood cross bridging


May be solid blocking placed perpendicular
between joists

Wood Floor Trusses


May be used in place of solid lumber
joists to provide support for the floor


Able to span longer distances than solid
lumber joists


Reduce or eliminate the need for
girders, piers, and columns


Allow for designing open spaces


Formed with top and bottom horizontal
chords and diagonal webs constructed
of standard size lumbers

Wood Floor Trusses


Typically placed 24” O.C.


Open web construction


Reduces sound transmission through
floors


Aids in ease of plumbing, electrical, and
heating systems installation


Sizes are determined from
manufacturers’ charts

Wooden I
-
Joists


Similar to wood floor trusses


May be used in place of solid lumber
joists to provide support for the floor


I
-
joists are able to span longer
distances than solid lumber joists


Speed construction


Very straight


May come with circular knock
-
outs

Wooden I
-
Joists


Formed with horizontal wooden (solid
lumber or micro lam) top and bottom
flanges, grooved to receive a solid
plywood or OSB vertical web

Joist Header


Used as rim joists with I
-
joist
construction


Can be used with truss construction


Should be strapped to the sill in high
wind areas


Double under exterior walls parallel to
joist direction

Girders (Beams)


Built
-
up


Formed with solid lumber nailed
together


Built on the job


Glue laminated lumber (glulam)


Solid, 1x__ lumber, glued together
under pressure


Graded according to appearance


Very strong


Able to span long distances

Girders (Beams)


Glulam (cont’d)


Disadvantages


Weight


Expense

Girders (Beams)


LVL (Laminated Veneer Lumber)


Glued veneers, similar to plywood


Advantages


High strength


Long spans


Disadvantages


Cost


Low moisture resistance causes
delamination in high humidity

Girders (Beams)


PSL (Parallel Strand Lumber)


Composed of veneers cut into strands


Very strong


Allows long spans

Girders (Beams)


Steel


Beam Types

S


standard W


wide flange

S
-

beam W
-

beam


I
-
beams come in two standards


Wide flange


Standard wide flange


Beam supports greater weight


More stable than standard S
-
beam


“W 18 x 62” means “Wide flange beam, 18”
tall, weighing 62 lbs/ft”

Girders (Beams)


Steel (cont’d)


“W 18 x 62” means “Wide flange beam,
18” tall, weighing 62 lbs/ft”


Advantages


Strength


Ability to span long distances


Disadvantages


Weight


Difficulty in cutting on the job

Girders (Beams)


Girder size


Determined by


Type of material used


Loads imposed


Clear span of the girder


Where loads exceed material limits, the
girder span must be reduced by using
piers, piles, columns, or posts

Girders

Types & Components


Drop girder


Flush girder


A ledger strip attached to the girder may
support joists


Metal connectors may support joists or
hangers attached to the girder


Where joists must tie to a steel girder, a
wooden plate must first be bolted to the
steel

Subflooring


Provides a base for the underlayment
and/or finish flooring material


Underlayment is material placed under
finish floor coverings (i.e. as carpet, to
provide a smooth, clean surface)


Underlayment can be combined with the
subfloor into a single thickness


Single thickness underlayment/subfloor
is generally constructed of ¾” tongue
and groove plywood

Subflooring


Materials


1 x ___ board lumber, applied
diagonally


Plywood or OSB 4’x 8’ sheets speed the
installation


Structural particle board and composite
board

Crawl Space Considerations


Access door is required


Recommended size 24” wide x 18” high


Large enough to allow for repair and/or
replacement of under
-
house mechanical
systems


Ventilation provided


Removes moisture from crawl space


8”x 16” vents are common