Great care is taken in preparing a specification for roofing or re-roofing to ensure the performance and longevity of the roof and that all products specified meet stringent quality standards achieving, at least, the requirements of BS5534.
Roofing battens probably account for the smallest material cost of the roof but should be treated with as much importance as any of the other elements of the roof build up. Unless working on an NHBC site battens do not have to be factory graded, despite the risks of defective battens or poor quality timber. However using ungraded battens will not meet the minimum specification standards required.
There are more risks associated with using ungraded battens – health and safety, contract stipulations, waste etc. Regulation is permanently tightening and standards for re-roofing now fall within Building Regulations. Building regulations may not insist on pre graded batten but how else do you establish that your batten is fit for purpose if it doesn’t meet the grade within BS5534?
Until 2006 graded roofing battens that complied with BS5534 were simply not available and the roofing trade had to cope with what was available. Grading on site was the only option. The best contractors selected the optimum supplier and selected accordingly.
The safest option is only allow factory graded batten to be used on site, which minimises the risk of defects. The view of the NHBC (who enforce only graded batten onsite) is that batten grading is not for the roofer to carry out but that the roofer should be supplied with the correct product that meets the British Standard, leaving only a sensible visual check before installation.
Responsibility for quality battens being installed lies with the sub-contractor, but what can you do for further peace of mind in the quality of the product? Firstly is it a clear requirement that battens complying with BS 5534 must be used? The optimum way to ensure this is to make pre graded battens part of the specification. These battens must be marked with the batten size, timber species, graded BS5534 and the supplier’s name. Evidence of third party accreditation should be insisted upon. You can also request the results of factory quality testing, any responsible manufacturer has factory control systems in place and by checking the results you can be assured that the product on site meets the standards required.
Secondly if the contractor is not using graded batten, checks should be made as to the extent and quality of the on-site grading that is taking place. The quality of a standard batten will vary greatly depending on the cut from either sideboards or the centre of the tree.
Health and Safety
Battens are a structural timber. Battens are designed to have adequate strength to carry the dead, imposed and wind loads on the roof. The HSE requires in HSG33 that battens meet BS5534 and are graded. If so 25x50mm battens can provide a safe foothold when fixing on rafters set at a maximum of 600mm centres. The batten grading rules have been designed specifically to meet these criteria. Battens are much more than just a fixing for slating and tiling but a structural timber designed to specific performance parameters, just like carcassing, scaffold boards and trussed rafters. Make sure they make the grade.