Manufacturer Russell Roof Tiles warns that specifying products simply because they meet minimum requirements can expose contractors and developers to far greater costs in the long run.
With the ongoing pressure of construction costs, substituting roofing components can look like an easy way to make savings. However, if the complete roof system has not been designed and tested to work together then there are hidden costs that need to be considered. Russell Roof Tiles is urging specifiers to look beyond headline compliance and consider the performance of the roof as a complete system.
Roofing standards have evolved significantly in recent years, driven by the need to improve durability, weather resistance and long-term performance. Nowhere is this more apparent than in dry fix roofing systems, which have become an increasingly important part of modern roof design.
Regional Sales Manager for Russell Roof Tiles Scott Summers has worked in the roofing industry for more than 40 years, initially as a roofer before progressing to manage a major roofing contracting businesses and then joining Russell Roof Tiles. From his experience, one issue that has repeatedly emerged is the attempt to value engineer roofing specifications which can sometimes create significantly greater costs further down the line.
The potential consequences can be substantial according to Summer, rectifying a failed roof where incompatible products have been installed can result in thousands of pounds of additional expenditure once the stripping-out, replacement products, scaffolding and potential disputes are factored in.
Following changes to BS 5534, the Code of Practice for Slating and Tiling, which strengthened requirements around mechanical fixing rather than relying solely on mortar, the introduction of standard BS 8612:2018 was an important milestone for the roofing sector. It specified that dry fix systems must achieve minimum levels of performance including resistance to wind loading and driving rain and snow, appropriate ventilation and long-term durability.
Russell Roof Tiles argues that this is where the specification conversation should begin rather than end. Two products may both achieve the relevant compliance requirements while differing considerably in their materials, design, durability and, crucially, their compatibility with the other elements being installed on the roof.
Roof tiles, ridges, hips, verge components, underlays, fixings, and ventilation products are not necessarily interchangeable. Products designed around one tile profile may not offer the same fit, weather protection or finished appearance when used with another. This means that seemingly minor product substitutions can undermine the thinking behind the original roof specification.
Summers said: "The question shouldn't simply be, ‘Does this individual product comply?' It should also be, ‘Has this combination of products been designed and tested to work together?' "If components haven't been developed as part of the same system, you are introducing an unknown into that performance."
The issue can also extend beyond physical performance to product guarantees. Russell Roof Tiles warns that using untested third-party components alongside its tile ranges without adequate test certification could compromise roof system performance and potentially affect the guarantees available on the finished system.
Material selection should also form part of the assessment. UV stability, structural integrity, and weather resistance can all affect how a dry fix component performs over its service life. Fire performance is also becoming increasingly relevant as rooftop solar PV installations become more commonplace, further reinforcing the need to think about the roof as an integrated assembly rather than a collection of standalone products.
Russell Roof Tiles has developed RussSpec around this whole-system approach. A bespoke RussSpec specification brings together the tiles, underlay, fixings, and ventilation products required for the project, with components engineered to integrate as a complete roof solution.
The company's technical team develops the specification incorporating factors including the building's location and construction requirements, while additional support can include site verification, training and compliance inspections.
RussSpec also provides a 15-year Design Liability Guarantee covering the integrated roof system rather than just individual roof tiles. Having a single manufacturer taking responsibility for the specification can become particularly valuable if an issue subsequently arises in the future.
For specifiers, developers and roofing contractors, Russell Roof Tiles believes the practical lesson is straightforward: Validate any proposed substitutions very carefully to ensure they are fit for purpose. The objective should be to engineer value into the roof without engineering performance out of it.
