Certified cheap and sustainable or unsuitable?

For many people, when it comes to the world of timber, what constitutes ‘sustainable’ and ‘suitable’ is a confusing matter at the best of times. John Park, from Canada Wood UK, gives an insight into the maze of markings and why Canada is at the forefront of certified timber products.

IT IS a very interesting phenomenon nowadays that, when it comes to specifying and using wood, the environmental lobby holds greater sway over the construction sector than does Building Control; large contractors quail under the eagle-eye of those willing to shin up Nelson’s Column to proclaim ‘Forest Crime’ lest they be unable to demonstrate satisfactory evidence of provenance of the wood they are using. I wonder if they would react any differently and if it would change their approach to procurement, if intrepid building control officers did the same to proclaim ‘Building Control ‘Crime’’ – timber used structurally does not have a grade mark; plywood sold as loadbearing and installed onsite does not have structural design values.

But it has a FSC mark, so that’s okay.

And even when appropriate materials have been specified by the building designer, studies
carried out have found that, in more than a few cases, contractors are increasingly influential in
product procurement and will put far more effort into changing a specification than they will into meeting it. Working to a price rather than to a specification, or up to a quality, is not unknown. So, how unfortunate then that much of the certified sustainable wood products sold into the building construction sector are invariably cheaper, because of their origin, than certified sustainable wood products which are also ‘certified suitable.’ Plywood with structural design values for example. Yes, it is available, but at a cost premium.

Alas, generally, certified legal and sustainable and marked wood products for use in construction do not come with an associated cost premium for this, because, sadly, the reality is that almost no-one in the construction sector is prepared to pay a cost premium for bonafide certified and marked sustainable wood products. So what chance the inevitably much more expensive environmentally certified material that is also fully accredited structurally?

UK Building Regulations permit different ways of demonstrating compliance but, whichever approach is taken, fundamental requirements in every case are the capability and suitability of specified materials. BS 5268-2 Structural use of timber – Part 2: Code of practice for permissible stress design, materials and workmanship has, other than industry association information, been the main source of structural performance data for wood and wood products. And that is another point worth bearing in mind, the plywoods listed in BS 5268: Part 2 are all manufactured and accredited in accordance with national standards – Canada, Finland, Sweden, USA – most other plywoods on the market are not.

And then came CE-marking. Instigated by the European Commission as the visible deliverable for demonstration of compliance for construction products in the European ‘single market’, it has provided the plywood sector, at least, with an unfortunate opportunity for perpetuation of obfuscation based on misinterpretation (and not entirely unintentional I’m sure...) by creation of the most misused term in the history of plywood mark(et) ing – ‘CE2+’ as an indication of structural suitability – it has nothing to do with it. The European Commission sets required levels of Attestation of Conformity (AoC) for factory production control for construction products which, once published in the Official Journal of the EU, are mandatory.

For structural plywood the required level of AoC is ‘2+’ – for factory production control.

Manufacturers started using the combination ‘CE2+’ for product marking as an indication of credibility and suitability and also, for good measure, tagging on ‘structural’ – this is a requirement in the appropriate circumstances.

What they don’t ‘tag on’ with ‘structural’, making its use most inappropriate, is the required
structural design values because they are not manufacturing to an industry standard on which this information can be based and in some cases there is no clear indication even of what wood species have been used.

There may be some instances of companies developing their own product standards and doing the appropriate testing, to determine design values, which is now allowable under the European Standardisation system providing they can demonstrate this with the necessary documentation.

BS 5268: Part 2 also now makes provision for this.

Currently in the UK there is the unfortunate anomaly that although construction products may have to meet the requirements of a European Harmonised Standard (HS) (products ‘placed on the market’ and manufactured in accordance with European Product Standards where these have replaced conflicting British Standards and where that option is chosen for demonstrating suitability for Building Regulations approval), they don’t have to physically carry a CE mark. (Strange, but true...) This is all down to UK Government’s interpretation of the Construction Products Directive (CPD). Encouraged by this and a number of other problems with the CPD, the EC is legislating for a change with the development of the Construction Products Regulations which, once approved and implemented, will impose mandatory application of the CE mark, throughout all EU Member States, to construction products covered by a HS.

The good news in all of this, is that the CPR will also impose a mandatory requirement for better market surveillance of construction products, full traceability back to the producer and transmission of product technical data at each change of ownership of the product along the supply chain. With your CE-marked construction product will come required ‘technical documentation’ so you will know what it is, what it is capable of and where it comes from and for load-bearing products have the requisite design data.

Canadian plywood and timber producers have been working along similar lines for generations already. Their raw material comes from the vast Canadian forest resource which has been managed for even longer, currently under the mandatory Provincial Forest Practices Codes, and there is now over 145 million hectares of forests managed under one of three certification systems – CSA, SFI and FSC. Certified sustainable and eminently suitable.