The development of floors

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

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The development of
floors

After the foundations have been completed and the external walls
constructed the construction of the floors commences. There are many
methods of construction which have developed over the last century. The
following slides feature some of these.

Bare earth or stone cobbles


The earliest methods of floor construction
was a bare earthen floor. The earth was
compacted and gradually dried out after a
period of time.


If the floor was to receive continual wear it
may have been cobbled. Cobbles are small
stones which are placed over the floor in
such a fashion that they form a continuous
solid surface.

Timber floors


Suspended timber floor joists are
supported by the walls which
transfer the load from the floor,
through the wall to the foundations.



The traditional method of providing
a flooring surface on top of these
joist’s was sawn timber boards
which had square edges. These
boards were butted together and
nailed down unto the top of the
joist.



The quality of the flooring boards
was improved by the addition of
tongue and grooved joints.

Floor joist

Square edge
flooring 150mm
wide and 20mm
thick.

Supporting
wall

Supporting
wall

Timber ground floors


If timber ground floors are used
ventilation must be provided beneath
the floor construction. The reason for
this ventilation is to prevent the
moisture content of the timber rising
above an unacceptable level (ie.
20%) which would create the
conditions for possible fungal attack.



Sheet materials such as plywood and
chipboard are now the most popular
coverings to floor joists. The most
common size of sheets are
1220mm x 2440mm.



Floor joists are usually placed at
400mm centres.

Positions for
ventilation

Joist spaced at
400mm centres.

Plywood
sheeting

Suspended T beam
concrete floor

Pre
-
stressed concrete

floor beams

Concrete blocks laid
between T beams

Pre
-
stressed
concrete floor
beams cast in
the shape of
an inverted T

Pre
-
stressed T beam concrete floors were one of
the first methods of creating suspended concrete
floors. The beams were set in position in such a
way that a 450mm concrete block fitted neatly
between the beams. The load of the floor was
transferred to the foundations by the beams.

100mm sand
and cement
screed on
top of beam
floor

Solid concrete floors


This is the most common type of
ground floor in use today where the
depth of hardcore fill underneath
the floor does not exceed 1200mm
deep.



The main requirements of any floor
are to provide a level surface which
is resistant to heat loss. A solid floor
must also provide resistance to the
passage of moisture from the
ground.



Insulation is incorporated into the
floor to prevent the loss of heat into
the ground underneath the floor.



Service pipes may also be
accommodated in the floor screed.

100mm deep sand
and cement screed

Insulation

100mm deep
concrete sub floor

Damp
-
proof
membrane (DPM)

Hardcore fill

Suspended concrete floors


HomeSPAN is the trade name for a
suspended concrete flooring
system which has recently been
developed for the domestic market.


This flooring system comprises of
flat precast concrete planks
generally 600mm wide and 150mm
deep. It can carry domestic
loadings up to 5m clear span.


These concrete floors have
excellent sound insulation and fire
resistance.


After settlement, cracking is
dramatically reduced as most
cracks results from the shrinkage of
timber joist.


Suspended concrete
flooring slabs.

Walls constructed to
support floor slabs.