BS 5534:2003 states the requirements for roofing battens, and includes information about the species, grades, treatment and required markings.
Most organisations, for example NHBC (National House Builders Council) LABC (Local Authority Building Control) and NFRC Co-partnership require fully-compliant battens.
NHBC now require that timber used for battens should be indelibly marked to demonstrate compliance with BS 5534.
Roof battens are not just to provide footholds for roofers, but are an important part of the roof structure itself.
They take the loads imposed by slates or tiles as well as loads from snow and wind.
Quality battens are increasingly seen as an important part of forming a secure roof.
Although not a legal requirement, BS 5534 sets out the standard for battens. The best way to ensure battens are fit for purpose is to choose those marked as BS 5534-compliant.
Manufacturers often add a coloured dye to their preservative treatment process, but this is not enough to show the battens meet BS 5534. Every batten must be indelibly marked showing:
British standards BS 5534 and BS 8000-6:1990 give the information you need for fixing and installation:
For trusses where the batten gauge is greater than 200mm
Ensure battens are a minimum size of 38mm x 25mm.
For longer spans than those given here, or for other loading conditions, battens should be designed in accordance with Annex E of BS 5534.
The tolerances for battens are:
Most battens are supplied with an industrially applied treatment process designed to provide a 60-year design life under Use Class 2. The relevant Standard is BS 8417:2011 Preservation of Wood.
Cut ends should be treated with brush-applied preservative, especially those in contact with mortar
Graded battens are usually graded, with the exception of a final grading for knots and wane.
Standard/Ungraded battens may be smaller than those allowed in BS 5534 or have other strength-reducing characteristics.
BS 8000-6:1990 Workmanship on building sites. Code of practice for slating and tiling of roofs and claddings, BSI.
Timber is the most sustainable mainstream building product. It is naturally renewable. Over 90% of timber used in UK construction comes from Europe, where more trees are grown than harvested (source: TTF Statistical Review 2016).
Softwood and temperate hardwood forests in Scandinavia, Europe, Canada and North America are stable or growing. Growing forests act as carbon sinks; wood products act as carbon stores.
Ask for PEFC or FSC Chain of Custody certification.
See Wood Campus RIBA CPD module Procuring Sustainable Timber for more on timber certification and sustainability and government requirements.