How well do you know roofing battens?

Shaun Revill, Trading Director at SR Timber, explains what to look for when assessing roofing battens and why knowing BS 5534 is important.


As awareness of the risk of substandard batten increases, it’s important for industry to understand what to look for and to find easy ways to identify correctly graded batten and inferior, sub-standard batten.

BS 5534, the code of practice for tiling and slating, is the British Standard covering roofing battens. It explains the grading requirements that a correctly graded batten should be produced to.

A roofing batten must conform to the grading criteria and allowed tolerances set out within BS 5534, otherwise it simply should not be used, and cannot be classed as fit for purpose.

BS 5534 is a critical piece of guidance but, within the document, grading rules for a correctly graded batten can be complex. Here are five simple steps you can use to check that the battens you buy, stock, sell and use are correctly graded and fit for purpose.

Due diligence

Due diligence is crucial throughout every step of the supply chain. This means ensuring that all documentation (including delivery notes) shows the name of the supplier and origin (imported and/or species code).

Knowing the batten has been graded in accordance with BS 5534 and the basic size or sizes, alongside the type of preservation and method of treatment, will ensure that the battens meet the standards expected by organisations such as the NHBC and LABC.
Having a full Chain of Custody Certification (either FSC and/or PEFC) will help ensure sustainability is managed throughout the supply chain. This certification requires suppliers to demonstrate that they are following strict protocols for sourcing, manufacturing and distributing their products.

Suppliers can only sell chain of custody products if they hold valid certification and can fully and correctly demonstrate sufficient due diligence against the products they declare as certified.

Spot checks

As well as the documentation due diligence checks above, we recommend carrying out spot checks on the product itself to check you are receiving a true BS 5534 graded batten.

If any spot checks are outside the tolerances allowed within BS 5534 you should not purchase or use the material, and we would recommend contacting your supplier and carrying out further investigations. Suppliers should always be able to offer documentation, guidelines on BS 5534 graded roofing batten and grading rules.

The whole supply chain has a duty of care to ensure any product they are either selling onwards or using conforms to all guidelines and any relevant British Standards.

Otherwise the products should not be purchased, sold or used.

Sizing

There are two sizes of graded roofing batten – 25mm x 38mm and 25mm x 50mm. The sizing tolerances of each differ slightly on the widths, but on the thickness the grading rules are the same.

BS 5534 requires the batten to be a minimum of 25mm in thickness – with an allowed plus tolerance of 3mm, so they can finish a maximum of 28mm (-0mm/+3mm).

For a 38mm batten, the width should be a minimum of 35mm to a maximum of 41mm, (-3mm/+3mm). A 50mm-width batten should be a minimum of 47mm to a maximum of 53mm (-3mm/+3mm). A good, graded roofing batten should be consistent in dimension, allowing the roofing covering to sit correctly when in situ.

If incorrect, the dimensions of graded roofing batten could impact the safety and lifespan of a roof. If battens are outside the allowed tolerances in BS 5534 when fixed, they simply are not correctly graded batten.

Knots

Similarly, knots on roofing battens can also impact the stability and safety of the roofing structure. If the knots are too large, or in the wrong position, they may compromise the strength and stability of the battens and, ultimately, the safety of the roof.

Any knot bigger than half the width of the batten, and appearing on both faces, is likely to be outside of tolerance and therefore not BS 5534 compliant.

BS 5534 also stipulates that roofing batten should not exceed a moisture content of 22%. A higher moisture content will likely also impact the lifespan of the roof and could impact the security of the roof coverings. Battens with a higher moisture content will shrink when in situ, and there is a risk that the batten nails will not stay flush to the batten.

If the batten shrinks, neither the roof tile nor slate will be securely fixed, causing them to become loose and at risk of being blown off in bad weather.

Markings

BS 5534 stipulates that roofing battens should contain markings and stampings that clearly show the manufacturer and point of origin. The dimensions of the batten should also be clearly visible on each piece, eg, ‘25×38’ or ‘25×50’.

It is essential that the batten is also marked as being ‘graded BS 5534’. If this is nowhere to be found, do not buy, sell, or use the batten.

Knowing these different signs to look out for will help merchants and tradespeople to sell, purchase and use only high-quality, reliable roofing battens that provide the right support and safety for roofing contractors – a vital step when dealing with such safety critical products.

www.sr-timber.co.uk