Timber Flooring Installation Guide
Essential information for customers, installers and contractors
General site conditions
Site conditions are extremely important and will make all the difference to the appearance and long-term success of your timber floor. Please make sure the following points are adhered to prior to your installation:
Ensure there is good access to the areas to be fitted.
Make space available for cutting/preparation.
Move/protect furniture prior to fitting.
Ensure all wet work (screeds, plaster work, painting etc.) is dry before the flooring is delivered to site.
Dehumidifying a newly built or extended property is essential. This can be achieved by running the heating system for a prolonged period with good ventilation and/or using a dehumidifier. In particular, all sub-floor concrete slabs and screeds should be dried to no more than 2% moisture content (1.8% if underfloor heated). Anhydrite (gypsum based) screeds should be dried to 0.5% on the CM scale (0.3% if underfloor heated). This will take approximately one month for every 25mm thickness of slab. Concrete sub-floors must be clean and flat and a self-levelling compound should be used to correct any unevenness. Where there is no underfloor heating, a damp proof membrane (DPM) can be applied once the screed has reached the required moisture level specified by the DPM manufacturer.
All existing flooring, plywood, flooring grade chipboard or MDF sub-floors must be in good structural condition, level and free from rot and fungus. New timber joists, battens and supporting timber should be kiln dried to no higher than 15% moisture content.
Immediately prior to, during and after installation, and for the lifetime of the flooring, the ambient temperature should be kept within the range of 15°C to 27°C and relative humidity in the room must be between 40% and 65%. Great care must be taken to ensure that the maximum sub-floor surface temperature of 27°C is not exceeded (please see below Additional points for installation over underfloor heating). Hot water pipes running underneath timber floors should be insulated to ensure the sub-floor surface temperature does not exceed 27°C. Responsibility for keeping environmental conditions within appropriate, recommended ranges, particularly after installation, remains with the Customer, who should also seek the advice of the contractor who installed/maintains their heating system. Failure to observe appropriate conditions may result in shrinkage, cupping, crowning, cracking etc. of the flooring.
It is recommended that measurements/readings are recorded prior to installation.
Timber flooring should be manufactured and supplied at an appropriate moisture content for the installation. It may be necessary to sticker out the flooring in the property to allow it to adjust (acclimatise) before fitting.
Key points with respect to fitting timber flooring
Solid timber floors should be glued, using a flexible adhesive such as Rewmar MS Polymer, and then nailed onto an 18mm exterior grade plywood or flooring grade equivalent subfloor.
Engineered timber flooring can be laid on a timber subfloor, nailed directly to battens/joists or alternatively glued direct to a concrete screed with a flexible adhesive.
Appropriate expansion gaps of 15mm should be left around the perimeter of the floor. These can be covered by skirting. For spans over 6m wide, appropriate gaps should be left at intervals across the entire floor.
If other trades follow the timber flooring installation, the use of temporary proprietary flooring protection is advised to prevent damage occurring whilst works are ongoing. It is essential that any such protection is removed once normal living conditions are adopted to avoid the flooring being overheated with resultant damage.