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.
Additional points for installation over underfloor heating
Systems that include concrete slabs and/or new screeds should be allowed to dry to the appropriate moisture content before commissioning (unless otherwise directed by the customer’s heating contractor/supplier). The system should then be commissioned prior to flooring installation by setting the system at the lowest level and gradually turning the heating up by 1 degree per day until it runs on the highest setting, and then down over a 7 day period. When it has been off for at least 24 hours, the sub-floor moisture content should be re-tested to ensure that the moisture content is appropriate for installation. The system should be turned off during installation.
After installing the timber flooring (and any time after the heating system has been off for a period of time), the system should be recommissioned slowly starting at the lowest level and increasing the temperature by 1°C to 2°C each day until normal conditions are reached.
The heating system must be set up and regulated to ensure a maximum running temperature at the sub-floor surface of 27°C. This temperature must not be exceeded under any circumstances. Above this temperature, the timber flooring may shrink, cup, crack etc. Hot water systems create a smoother flow of heat than electric systems, which can be prone to hot spots. It is not advisable to lay insulating materials of any description (e.g. protective sheeting, rugs, carpets etc.) on timber flooring whilst the underfloor heating is operating as this could create hotspots that may compromise the floor.
Some systems allow for the installation of thermostatic sensors on the screed surface to ensure a maximum temperature is not exceeded. Regardless of the controls employed, ensuring the maximum sub-floor surface temperature of 27°C is observed before and after installing the timber floor is the responsibility of the Customer who should also seek the advice of their contractor or heating specialist.
Maintaining your flooring and keeping it looking its best
Keep floors dust and dirt free using soft brushes/vacuum attachments. Only use the recommended cleaning products and systems for your floor/floor finish and do not use these for a minimum of 1 week after fitting to ensure the finishes are fully cured. (You must adhere to the instructions for the product(s) recommended for your floor/floor finish since guidelines and curing periods vary.) Clear up any liquid spillages immediately. Never soak floors or use excessive levels of moisture. Only use mops which are designed for use on timber floors (ordinary mops may retain and apply too much moisture). Do not leave damp materials on wooden floors. Use protective pads under all furniture that comes in contact with the floor.
Timber floors will expand and contract with seasonal changes, resulting in changes to the moisture content of the wood. To manage and minimise changes, maintain relative humidity levels between 40% and 65%. In addition to ensuring that sub-floor temperatures do not exceed 27°C, make sure that heating systems are not run too hot to avoid excessive movement in the timber – as a guide room thermostats set to 21°C or lower is ideal.
For further information, please ensure that you have and refer to a copy of the Company’s Maintaining your timber flooring document together with specific cleaning and maintenance information for your floor finish.
These are general guidelines only and no guarantee or warranty is either offered or implied herein as to the suitability of any flooring product for any specific purpose.