FLOORING
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TOPIC CHECKLIST
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Is it a structural or decorative floor?
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How much wear will it be subject to?
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What changes in humidity will it be subject to?
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Does it have the correct moisture content?
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Have you acclimatized it to the building?
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Have you left sufficient movement gaps?
What are the main types of wood flooring?
Solid wood structural
Square-edge softwood boards, fixed to support battens with nails or screws. The gaps between the boards will change with changes in moisture. They are normally covered by another material, but sometimes used for a rustic look. Use normal trade stock.
Solid wood decorative
Softwood or hardwood tongue and groove boards. They can be secret-nailed (fixed), clipped (floating) or stuck directly to the sub-floor. The boards must be kiln-dried to 8-10% moisture content.
Engineered
Engineered/laminated flooring is more stable than solid wood flooring, as it is made from a solid wood layer bonded to an engineered core, such as plywood. Often recommended for use with underfloor heating, or for areas subject to extreme moisture changes, such as kitchens and bathrooms.
Most engineered wood flooring is now designed with a click system that makes installation simple. Use the manufacturer’s recommended underlay.
Parquet
Use directly over a continuous supporting surface, such as a base of concrete, wood or plywood.
Before you begin
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Allow the wood to stabilise to the room’s moisture conditions for at least 24hrs (48hrs for hardwood) before fixing
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For installations over underfloor heating, ensure the moisture content of the boards is between 6% and 8% at the time of laying
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Ensure that any cement sub-floors register a relative humidity (RH) reading of no higher than 75% (65% or less for underfloor heating installations or for floors intended as stick-down installations) when tested with a hygrometer
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Ensure all wet trades (plasterwork, screeds etc.) have had time to dry out fully before installing the floor
Choosing the right species for your job
For most domestic use, any species with a medium or small movement will be fine. For commercial use or for areas with heavy traffic, choose a species with high wear resistance.
For underfloor heating, or for areas subject to extreme moisture changes, choose low movement species or engineered flooring (refer to manufacturer’s guidelines).
Board thickness
When fixing boards to support battens or joists, choose a thickness of board appropriate to the span of the batten or joist to avoid deflection and squeaking.
Finished board thickness | Maximum span (centre to centre) |
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16mm | 505mm |
16mm | 600mm |
21mm | 635mm |
28mm | 790mm |
Movement classification | Commonly used species |
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Small | iroko, teak, merbau, American mahogany, dark red meranti, Western hemlock |
Medium | European redwood/whitewood, ash, European oak, American white oak, maple, sycamore, European cherry |
Large | beech, birch, sweet chestnut |
Level of traffic | Suggested species |
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Light Domestic | European redwood/whitewood, idigbo, European birch, Douglas fir, and light red meranti |
Normal Schools, hotels, hospitals, shops | teak, afzelia, iroko, dark red meranti, keruing, merbau and sapele |
Heavy Traffic lanes in public buildings | European beech, European oak and rock maple |