BS 5534 was first put into place in 1978 and over the years has been updated and now it has become a fairly substantial document which covers all the roofing components in relation to slated and tiled pitched roofs. In this blog post I will be going over the main points which the new 2018 amendment to this standard puts in place.
The scope of the British Standard is to give recommendations for the design, performance and installation of new build pitched roofs, including vertical cladding, and for normal re-roofing work, including repairs. The code of practice should be taken as a guide with recommendations and not as a quoted specification.
The 2018 second amendment supersedes the previous 2015 amendment, which will be withdrawn on 1 July 2018. The second amendment incorporates changes including; referencing BS8216 (Specification for dry-fixed ridge, hip, and verge systems), clarifying scope for heritage roofing, recommendations for roofing underlays and adding new terms and definitions.
In regards to heritage roofing, particularly where traditional or reclaimed materials are used, it is accepted that this British Standard might not be appropriate. Fixing methods for traditional roofing materials often conflict with BS 5534, and consultation with local planning authorities and/or conservation experts is advised, so a suitable approach can be agreed. This is a common sense approach and takes into account the feasibility of the new standard on the heritage stock.
The standard outlines the purpose of a roofing underlay which includes reducing wind uplift and providing a secondary barrier to prevent water ingress. The new amendment adds to this the necessity for an underlay to provide temporary weather protection before the installation of the primary roof covering. This is because if an exposed underlay is subjected to UV light, heavy rainfall or snow it could lead to premature failure. It notes that if an underlay is being left for a period of time by adverse weather it should be protected by the likes of a tarp. I think this addition to the standard takes into account the reality on the ground as it is inevitable that a roof underlay will be exposed at some point during the construction process.
The final major change is the introduction of BS 8216:2018. This is a new standard which has been put in place to combat the poor installation of dry fix roofing products. BS 5534 urges users to pay particular attention to the resistance to wind loads, rain resistance and durability performance of dry fix roofing products stating that dry fixed ridge, hip and verge products should conform to BS 8612.
The British standards are a great resource for assisting to specify a roof covering. If a contractor is offering a specification that does not look up to scratch then either the manufacturers instructions or the British standards which the manufacturers will be working to will keep you in the right. For more on a range of roofing topics please check out some of my other roofing blogs where discuss various roofing defects.