floors Flashcards
how was natural wood cleaned in the olden days vs now
in the old day’s water and waxing
now today waterproofing membranes and sealants are available which
has made it easier to clean .. soap and water
what are the technical terms form the moister in and moister out regarding wood floors
The absorption rate and desorption rate
how can you overcome the difference between the absorption rate and desorption rate
By using treated wood and by sealing the finished floor surface
what happens to wood when it is too dry or too wet
dry: create gaps and crack
wet: pop up
What type of damage can the humidity from the ground or a concrete slab cause
it can cause the wood to get fungus or rot.
Natural wood is a more expensive form of construction than a solid floor or a laminate and therefore it is only used:
In houses built in timber construction (frame works) – min airspace 450mm
• On sloping sites, which would need a great deal of filling to make up the ground to the required floor
level – min airspace at lowest point 450mm
what is the construction method for a natural timber floor on a existing concrete ground floor slab (23)
• The existing floor finish is removed and the screed is cleaned • To prevent moisture flow from the existing concrete / screed into the timber floor, a plastic sheeting or bitumen is applied to the surface of the screed. The entire timber floor has a ventilation gap of 10mm all around the walls (skirting area) which ensures enough airflow to keep the timber floor intact. If the area is too big, ventilation gaps are placed into the floorboards. • Timber bearers are laid parallel at the shortest distance at 400 c/c on top of the sheeting • Floor boards (T&G) are laid on top at a 90 degree angle. They are sanded and sealed.
*in short:
existing floor removed - screed cleaned- plastic surface (10mm gap all around) - timber beamers laid (min 400c/c)- timber boards laid @90 degree on top of beamers- sand and seal
Natural wood ground floors are
susceptible to dry rot and are said to be colder than other forms of flooring. For that reason, the
National Building Regulations (Part J – Floors) demand that:
“Any suspended timber floor in a building shall be provided with adequate under – floor – ventilation
and provision for ventilation and the protection of ventilation openings must be guaranteed.”
The problem of dry rot, which is a fungus that attacks damp timber, how can this be overcome
• Always using treated woods
• Providing adequate ventilation-space under the floor (min 125 mm)
• Positioning the damp-proof courses correctly (plastic sheeting on concrete surface or bitumen)
to keep the under floor area and timber dry.
• Placing airbricks at 1.5 to 2 metre intervals (at least two per wall)
• Always sealing all the floorboards before use
why is it essential to keep moisture out of the floor, and how is this achieved
moisture allows fungal growth to take
place. This is achieved through adequate ventilation.
*The usual method is to allow a free flow of air under the floor covering by providing airbricks (in
outside walls at approximately 1500 to 2000 mm centres around the perimeter of the building and a
waterproofing sheeting or bitumen underneath.)
what are the regulations around the construction of natural wood floor on ground level (24)
The foundation wall has to be doubled up to be able to carry the wood
floor and extends a minimum of 400 mm over the N.G.L. Airbricks are
placed at 1.5 to 2 metre intervals
• A DPC layer is placed on top of the airbricks layer
• The ground inside the walls needs to be clean of all vegetation, preferably chemically treated and filled with 20mm clean crushed stones
• Bearers on brick piers or sleeper walls in honeycomb bonds are used if the length for the joists gets too long. They always end with a DPC layer.
They need their own foundations (see detail)
• Joists span the shortest distance between walls; this means that joists
could either be parallel or at right angles to a fireplace. All joists rest on
wall plates on the walls
• To prevent bending / twisting of the joists, joist-spacers are placed in between.
• Thermal insulation and waterproofing is placed on top of this structure.
• Floor boards (T&G) are laid on top and are sanded and sealed.
• The 10mm ventilation gap under the skirting board is strictly applied
here.
when are suspended natural wood floors on ground level used
when the design asks for level
differences on existing concrete floors.
*The same design aspects and regulations as for natural wood floors
applies
construction of suspended natural wood floors on ground level (25)
•Air bricks have to be built into the existing outside wall around (at least
on two opposite sides of the timber floor area. The level for the airbricks
is the top of the concrete or cement screed. At least 2 airbricks per side.
• The floor finish is removed and plastic sheeting is laid on top of the concrete / screed over the whole area.
• Honeycomb sleeper walls are erected on top (min. 1 brick = 75mm) and covered with DPC.
• Wall plates rest on the sleeper walls and the joists lay at 400mm centres on top, parallel, spanning the shortest distance.
• 10mm gap around the sides for ventilation is essential
• The floor boards (T&G) are placed over the area, they are sanded and
sealed.
- CALCULATION – HELP:
- Joist size: 50mm +span x 0.5 divided by 10 = width
- For spans exceeding 3 metres, add 10mm for every additional metre
in short
airbricks- plastic -(10mm air around)- joists 400c/c - timber laid- sand and seal
laminated timber floors can be provided to resemble any ‘real wood’ finish. What are the Two different ‘laminates’ exist
on the market?
- Natural wood laminates: Softwood is laminated together with a hardwood wear surface
- Decorative wood laminates: A core (usually a high density fibreboard) provides the
thickness and has a thin layer of special ‘Kraft paper’ impregnated with thermosetting resins laminated to the top and bottom (bonded by heat & high pressure) The top layers incorporate a decorative paper (treated with Melamine & a protective overlay) that provides the design.
how are laminates applied to a cement screed
they are either glued or they just
‘click’ into each other.
