Jenni Forest, quality manager for JB Red at Marley, explains what to look out for when choosing battens.
Roofing battens are one of the most important parts of a pitched roof structure, acting as a structural and load bearing element, and that’s why using an inferior quality product is a serious risk for your own safety and reputation. As well as supporting the dead weight of tiles, and the imposed wind loads, BS 5534 graded roofing battens can also be used as a secure foothold during installation, which makes checking the quality and compliance of the roofing battens you are using imperative.
So, as well as making sure your battens are stamped as BS 5534 compliant, what else do you need to check for? Here, we answer some common queries about batten quality:
- What batten defects are allowed under BS 5534?
As a natural material, timber battens will obviously have varied characteristics but BS 5534 is very strict about what is and isn’t allowed and our machine grading process scans battens by the millimetre to make sure they meet the requirements of the standard.
Some knots are allowed, depending on their size and position. If a knot appears on both sides of the face, the sum of the knot on both faces must not exceed the width of the batten. A knot appearing on both sides of the batten, which does not appear on the face, is only deemed permissible if the knot on either side is one-fifth of the depth or less.
BS 5534 also allows for a missing corner on the batten, otherwise known as wane. However, it is only permitted on one axis and should not exceed one-third of the dimension of each of the faces on which it occurs.
For a full list of permissible defects, we have put together a free pocket checklist to help you ensure you are using quality, compliant battens. For your free copy, email info@marley.co.uk
If you have any doubts about a possible defect, check with the manufacturer before you use the batten.
- Do battens have to be completely straight?
Battens need to be straight, so BS 5534 sets a tolerance on distortion. Bow, spring or twist should each not be greater than 5mm, measured over a length of 1.2m at a reference moisture content of 20 per cent. If your batten is bowed more than this, then do not use it and check with the manufacturer.
Battens cut from sideboards are less likely to distort which is why JB Red battens are only manufactured from kiln dried sideboards.
- Aren’t all graded battens the same?
If you have two battens from different manufacturers, both graded to BS 5534, many people would assume that they are the same. However, this may not be the case and just like other roofing products, there can be significant variations in quality and performance. Indeed, it is surprising how many differences there can be between similar looking roofing battens – from the way they are graded, through to the type of timber they are made from, the quality processes they go through and the preservatives they are treated with.
To make sure contractors know how to choose the best quality battens, at Marley we are carrying out an education campaign to ensure our customers know how to spot the differences between graded battens. This includes the launch of our new batten training, as well as the free pocket checklist.
- Are all coloured battens BS 5534 compliant?
No. The issue of batten colour has caused some confusion. Whilst the distinctive red colour of our JB Red battens does give peace of mind that you are using a BS 5534 compliant batten, along with other coloured battens from reputable manufacturers, this is not necessarily the case for all battens. Please don’t assume that just because it is coloured that a batten meets the required British Standard. It must also have the correct stamps and supporting documentation.
