BS 8612 – A Watershed For Pitched Roofing

Redland – the company that invented dry-fixed roofing systems, with patents dating back to 1966 – has welcomed the introduction of BS 8612 Dry-fixed Ridge, Hip and Verge Systems for Slating and Tiling, published on January 31st.

The new standard is a product specification which frames minimum performance requirements for dry-fix roofing components: establishing that they are both fit for purpose and are delivered with sufficient information to ensure correct installation.

The introduction of BS 8612 is a response to an increasing number of, particularly, dry verge failures; primarily because of installation errors, but also contributed to by product design.

In 2011, NHBC analysed its claims figures and discovered that 60% of them were related to roofs and of all roof-related claims, over half involved mortar which led to the changes in NHBC guidance in 2012

Dr Kevin Ley, Technical Manager of Redland, says: “Since BS 5534: 2014 – which brought about a step-change in the requirements for fixing of pitched roofs both for roof tiles and ridge, hip and verges – we have seen an acceleration in the move away from traditional mortar fixing to modern dry-fix.

Unfortunately, the resulting increased demand for dry-fix products and a lack of standardised performance requirements allowed products of questionable fitness for purpose to enter the market. The resulting problems meant there was a significant risk that past mistakes concerning mortar fix failures would be repeated”.

Many developers have migrated to dry-fix systems as they are far faster to fit than double-fixed wet systems but poorly performing and poorly installed dry fix systems have been leading to roofs with problems

Though dry-fixed products have been on the market for decades, demand has burgeoned over the last five years. As a result, there’s also been a growth in the number of companies supplying lower cost, and often lower quality, products. The switch from traditional wet fix to dry fix was initially driven by changes to NHBC guidance. In 2011, NHBC analysed its claims figures and discovered that 60% of them were related to roofs and of all roof-related claims, over half involved mortar.

This led to changes in NHBC guidance in 2012 which said that all bedded ridge and hip tiles had to be mechanically fixed, and then ultimately to the 2014 revised version of BS 5534 Slating and Tiling for Pitched Roofs and Vertical Cladding – Code of Practice which standardised these changes.

Problems include ridge and/or hip tiles blown off by the wind; dry verges hanging from roof edges, or unsightly black staining down gable-end walls

As a result, many developers have migrated to dry-fix systems as they are far faster to fit than double-fixed wet systems. However, the purchase of poor performing dry fix systems, or the failure to install quality components correctly, leads to roofs with problems. For example, this may mean ridge and/or hip tiles blown off by the wind; dry verges hanging from roof edges, or unsightly black staining down gable-end walls due to verges which do not shed rainwater properly. The latter problem of verge failure to shed rainwater away from the wall at worst can lead to penetrating damp and compromise cavity wall insulation.

The introduction of BS 8612 is a response to an increasing number of, particularly, dry verge failures; primarily because of installation errors, but also contributed to by product design

Dr Ley concludes: “The publication of BS 8612, the first-ever product standard for dry-fixed ridge, hip and verge products in the UK, is, therefore, an essential and welcome landmark for the industry. Not only will it ensure that dry-fix design and installation standards are raised; but also that developers, contractors and building owners get the product quality and performance they deserve”.

Redland has produced a handy guide to the new standard which can be downloaded from redland.co.uk/bs8612.