Roofconsult Website Are Roofing Batten Standards that Complicated? by Mike Hartley of John Brash Ltd
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Not if you buy the correct timber, argues Mike Hartley, Chairman and Managing Director of John Brash.
“Debate continues as to whether it is practical to grade on site. In all other areas of the timber trade, this would not even be questioned, simply because ungraded or incorrectly graded timber would not be tolerated with the same relaxed manner. Picture1
It is of course accepted that battens do need to be graded and the grading rules that have been set are designed to account for the loads that will be imposed upon them. To help with this process, we have just updated our on-site grading guide to reflect the recent changes to the new British Standards - BS5534:2003 +A1: 2010.
The new Standard rectifies an anomaly in the previous version that permitted an excessively large knot that was almost 3/5th of the batten thickness, equivalent to 15mm on a 25mm thick batten.
The new standard has reduced the maximum allowable size of through-knots (a knot appearing on both edges but not on the face) to only 5mm, significantly smaller than the previous version’s 15mm.
There is also now a requirement for battens to be straight, with specific new tolerances for distortion that cover bow, twist and spring.
Whilst these two defects were not historically found in most typical roofing battens, rising timber prices has heralded alternative methods of cutting battens and the defects have become more common.
That’s why John Brash has consistently used the traditional side-board material for roofing batten manufacture. With both trained staff, and stringent processes, in place we ensure that any other type of sub-standard material reaching our site is immediately identified and quarantined to prevent batch contamination. That’s why we constantly urge all roofing contractors and specifiers to check that the batten they are supplied with is either fully factory graded, or manufactured from material that is suitable for on-site grading by competent persons. Picture2
Ideally, a roofer should be presented with an independently certified, fully graded product, which requires no grading on site. Many in the industry are beginning to recognise this and adopting the stance that it shouldn’t be the roofer’s problem to grade battens.
Shades of grading
Of course, the issue of grading is not in question here. The batten is such a safety and performance critical element of the roof that it is universally accepted that they should be graded. Therefore, there are two options available to roofers:
1) Buy a fully graded batten that carries independent certification that it has been graded and meets the standard.
or
2) Buy a batten to grade on site.
The first option is the preferred route as it means that the batten is fully compliant with BS5534:2003, the code of practice for slating and tiling. It also means that the responsibility for ensuring the batten is to the required standard rests firmly with the manufacturer, which reduces the burden on roofers and allows them to concentrate on the job in-hand. This is important as even the most proficient grading on site can be affected by site conditions such as the weather and time pressures.
One of the issues facing the industry is that there are battens which claim to be graded but don’t carry this independent certification. Without it, there is no way of knowing if the batten has been correctly graded and if this is the case, alarm bells should be ringing. John Brash became the first in the industry to offer JB-RED factory graded battens, to BS5534:2003, which also carry the BRE ‘Tickmark’ 3rd party accreditation. Picture3
John Brash’s JB-RED provides a factory graded batten that is fully compliant with the new requirements of BS5534:2003 +A1: 2010, the code of practice for slating and tiling. Our advice remains: beware of battens that claim to be British Standard factory-graded but do not carry independent third party accreditation. The Building Research Establishment (BRE) have carried out tests, which showed that over half of the battens tested, which claimed to be factory-graded BS5534:2003, fell well below standard – this is of great concern.
It continues to be an option to grade on site. However, this is only a practical solution if the correct timber is used, in which case it can be done by the roofer. Battens suitable for on-site grading should have already been graded for rate of growth, slope of grain, rot and decay, dimension and species. The only items to grade for therefore should be face knots and wane. These can be assessed on site providing the grader has been trained to do so.
Our aim is to make life easy for the roofers when using battens, which is why we offer factory graded battens as well as our newly updated on site grading guide.
In summary, if your supplier offers you factory graded battens to BS5534:2003 ask for independent assessment. If they have it they will give it to you. It really is that simple.
For information on the John Brash range of products visit: www.johnbrash.co.uk or telephone: 01427 675588.
 
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