Our Group Chief Operations Officer, Andrew Morley explores amendments to BS5534, the slating and tiling standard, 12 months on from the latest updates, which drove the sector towards dry fix systems and away from the mortar based approach.
Over many years the roofing sector has evolved in terms of materials, products, and techniques used in mainstream roofing situations.
Underpinning those changes have been the updates and amendments to regulations, of which the most prominent is BS5534. Originally introduced in 1978, the slating and tiling standard has undergone many updates to reflect quality improvements and raised specifications in line with product development, performance standards, and customer expectations.
The latest iteration was just 12 months ago, which built upon the changes first introduced in 2015 that drove the sector in the direction of dry fix systems and away from the traditional mortar-based approach. This was much more of a system-based concept with the mechanical fixing of single lap tiles, hips, and verges that are now the accepted norm.
If we cast our mind back, the logic behind the 2018 changes was to improve further the security, durability and weather tight properties of roofing systems with minimum standards for the manufacturer’s products and took a more rigorous approach to testing and installation. Both challenges that the industry has responded well to.
Avonside Group Operations Officer, Andrew Morley discussing BS5534 amendments Another key area of concern addressed was related to wind uplift and the guidelines were amended to address this factor. The 2018 amendments to BS5534 recommend a maximum drape of 15 mm in order to prevent the transfer of wind loads to the roof covering which it was not designed to resist.
In addition, the directive was designed to ensure underlays are not exposed to the elements for more than a few days to avoid damage from weather extremes that render it unfit for purpose.
Further guidance is given if exposure is anticipated. In these cases, the use of a tarpaulin cover or similar is acceptable. Finally, in this area, the classification for underlays in relation to UK exposure zones was re-drafted and updated.
The use of counter battens above underlay now needs to be designed in such a way to ensure that the eaves detail avoids troughs or a negative slope, allowing any surface moisture to drain into guttering.
These changes were implemented largely in response to previous system failures. For example, the National House Building Council (NHBC) reported that two-thirds of all their roofing failures were mortar related. So, the updated regulations were a welcome evidence-based improvement that addressed unsatisfactory methods.
The uptake of BS5534 in the new build sector has been pretty well universal, although this appears to be less the case in terms of re-roofing where we still have some way to go to secure the same level of adoption.
“We have found that the adoption of dry fix has reduced our overall level of callbacks, which is a significant positive.”
In general terms, the regulations have been welcomed across the sector and represent a solid piece of regulation that was well thought through and progressive. They have been a positive example of the drive for quality installations, which benefits all parts of the supply chain and results in increased customer satisfaction, fewer callbacks for defective installations and better protection against the elements.
How Avonside Have Found the Amendments
In our own experience, we have found that the adoption of dry fix has reduced our overall level of callbacks, which is a significant positive. The initial cost of training operatives in the new systems has more than been compensated for by this reduction.
Additionally, the new guidelines on underlay zones have contributed to a better-quality roof installation, and Avonside is currently reviewing areas we would like to see included in the next review of BS55534.
So, from our perspective, we would contend that updating BS5534 has achieved a successful outcome for the roofing sector and its clients.
Andrew originally wrote this column for the July edition (issue 83) of Roofing Today magazine (page 44).