These may be chastened economic times but timber decks and boardwalks remain popular features of home building and renovation, commercial developments and landscaping projects. As a consequence, demand for decking has earned a reputation of being somewhat recession proof with the value of sales in the order of £130m in 2011, very similar to 2010.

However, the uncertain economic times of the last couple of years have put downward pressure on costs in the fight to win business. In the mass-produced consumer decking market, competitive pressure has resulted in substitution of premium grades of timber with lower specification and visual grades. This is not a trend unique to redwood and whitewood decking and it also affects the higher value hardwood sector with substitution of high performance species with lower cost hardwoods that have less well-defined performance characteristics.

The swing to "general decking grades" of softwood and the growing availability of a wider choice of hardwoods is not without its customer relations consequences. The Timber Decking & Cladding Association (TDCA) is experiencing a significant rise in requests to provide expert, independent comment to help resolve disputes over the quality of decking. While cases are usually brought to TDCA by loss adjusters seeking advice on alleged defective materials claims, there has also been an unprecedented rise in commercial and domestic property owners seeking to commission the TDCA inspection and report service.

None of the cases referred to the TDCA relate to timber that is manufactured in accordance with the DeckMark quality scheme for decking materials and in the 12 years the scheme has been running, only a handful of disputes about timber quality have arisen. This is particularly impressive when set against the massive volumes of softwood and hardwood decking sold since 2000. The record of DeckMark-accredited manufacturers is a tremendous testimony to quality, particularly when compared with the level and frequency of disputes involving lower specification decking now being brought to the TDCA’s attention.

Quality compromises
Our experience shows that while professional designers tend to follow good design practices, it is at contract bidding or installation stages where competitive pressures often result in compromises on quality. In recent years, the mass-produced deck board market has moved away from premium grades like Scandinavian 5th or Russian 4th down to 6th grade or general decking grades which tend to machine less well than premium grades and are characterised by a greater frequency and size of knots and surface defects like splits, lines of unstable pith and dead knots, which can disintegrate and fall out. Another significant change in material specification is in softwood board thickness, with a swing from boards that are nominally 38mm thick to nominally 32mm thick, requiring closer joist support centres.

The current decking market has more variety of choice and grades of timber quality than ever before and can be a minefield for the unaware. Dissatisfaction with the quality of decking materials is now the major cause of disputes between suppliers and the property owner. So, while offering a general or unproven grade of decking may seem like a good business tactic, when it comes to customer satisfaction it can turn out to be a costly false economy.

For certain sectors of the market, some of the general decking grades are perfectly acceptable, being milled and preservative-treated to specifications set by an individual timber importer or distributor. However, across the supply chain as a whole there is wide variation in the finish quality and performance of both softwoods and hardwoods.

If visual appearance and long-term performance are important it is vital that contract documents and the design specification are in the kind of detail promoted in TDCA guidance documents.

When we are called in to inspect alleged defective materials, the starting point is always to ask what was specified. All too often, all that is specified is "treated softwood" or "oak decking" and essential details about the species and visual grade required, treatment use class, durability and sapwood exclusion, service life and moisture content at time of installation are absent.

We’re keen to raise awareness about the consequences of specification compromises to reduce cost. A key aim of the TDCA is to help those responsible for commissioning decking projects to better understand the benefits of using sustainable softwoods and hardwoods certificated under the DeckMark quality assurance scheme for decking materials. A decrease in the number of disputes about the quality of decking materials will be a key measure of whether buyers have listened.

As part of the campaign, the TDCA is making its technical bulletins and its Code of Practice for Raised Timber Decks, which is endorsed by NHBC, available free of charge.