Timber Flooring Consultancy

Although BS 8201 provides general guidance on the moisture content that timber flooring will generally settle to in different environments, it is important to note that these values can vary.

When specifying a moisture content for timber flooring, you should give special consideration to the heating/air conditioning regime in the building where the floor is to be installed. For example, a conservatory in a house or a glazed atrium in a commercial building may be subject to significant solar gain.

You will find guidance on specifying and achieving the appropriate moisture content in the BM TRADA publication Wood flooring: A professional's guide to installation.

Many timber species, both softwood and hardwood, are suitable for timber flooring. Key considerations are appearance and performance, especially resistance to wear and movement characteristics.

A list of species suitable for flooring, including their movement classification and density, is given in BS 8201. Note that some of these species are not commercially popular or readily available. However, you should find it relatively easy to source alternative timbers that can be used in their place.

You can find guidance on selecting appropriate timber species in the BM TRADA Wood Information Sheet Decorative timber flooring.

BS 8201 advises a screed drying time of one day per millimetre for the first 50mm, with a longer period being allowed for thicker screeds. Type of construction, screed mix and weather conditions will also have an impact on drying time.

In all cases, you should monitor at regular intervals the humidity levels in the screed to ensure that it is at an acceptable limit before installing the flooring. Methods for monitoring humidity levels are included in Appendix A of BS 8201.

You will find guidance on assessment and preparation of a sub-floor in the BM TRADA publication Wood flooring: A professionals' guide to installation.

This is an important and often complex consideration, and the correct detailing will depend on the demands of your particular flooring design.

It is critical that you have enough provision for expansion (or shrinkage) across the width of the floor, or there may be an increased risk of the development of defects or failure of the floor in service. You should also allow for peripheral gaps around the perimeter of the floor and at its junction with other abutments, and gaps from the bottom of the skirting and around service pipes.

You will find guidance on the provision of expansion gaps in BS 8201, in the BM TRADA Wood Information Sheet Decorative timber flooring, and in the BM TRADA publication Wood flooring: A professionals' guide to installation.

It is generally accepted that on-site storage prior to installation of pre-finished, factory-dried flooring should be kept to an absolute minimum and that packs of flooring are kept wrapped within their original wrappers until required.

Where on-site storage or acclimatisation of timber flooring is considered necessary, it is vital that the storage conditions are as close as possible to the expected in-service conditions. This will help the timber to achieve its 'equilibrium moisture content' (EMC) and keep the in-service moisture content of the floor to an acceptable minimum.

Follow the flooring manufacturer's recommendations and moisture content guidance in BS 8201 to ensure that you specify appropriate moisture content for the timber. You should have this checked by the installer immediately prior to laying.

Fixed flooring is where the flooring components are nailed down to the underlying battens or joists, resulting in a 'captive' floor surface, with each individual flooring component fixed firmly to the sub-floor.

Specification of fixing for solid timber flooring and modern multi-layered, engineered boards will depend mainly on the type and frequency of fixing and the nature of the substrate.

Fixing is carried out using nails, screws, staples or adhesives and guidance for using these methods is given in BS 8201.

However, it is recommended that you always seek and follow the flooring manufacturer's guidance and recommendations for fixing and for any proprietary sub-floor systems.

You can find guidance on flooring installation and fixing techniques in the BM TRADA publication Wood flooring: A professionals’ guide to installation.

Floors squeaking in service, particularly when subjected to foot traffic, can be caused by a number of factors – and often more than one.

One of the main causes is physical movement of the floor structure due to moisture-related shrinkage of timber components and resulting friction between these components. Other factors include excessive notching or drilling, insufficient strutting or the suitability of fixings.

Consult the BM TRADA Wood Information Sheet Timber joist and deck floors – avoiding movement for specific guidance intended to minimise problems of movement and noise in timber floors in masonry or timber frame buildings.

Although timber flooring can be left unfinished to wear naturally, sealing keeps your floor clean and minimises damage and wear. However, the process does not end with application of the final seal coat. Maintenance and aftercare considerations similarly influence long-term performance and service life.

Your choice of finish will depend upon several factors, such as the desired appearance, slip resistance and wear resistance.

A large number of floor sealing options are available – ranging from oil and wax finishes that require frequent maintenance but are simple to reapply, to polyurethane lacquers that generally provide more resistance to wear, but damage is difficult to repair.