New EWI specification tool offers new build and retrofit knowledge and compliance assurance

A new tool is helping architects and specifiers source compliant, high-performing external wall insulation (EWI) solutions in just a few clicks.

The system selector is a one-stop-shop specification system for building façades. It allows users to view entire systems and find options to match their commercial and residential projects.

EWI Spec Tool

It filters from the many EWI options across webertherm XM, a multi-layer, lightweight, thin-coat render system, and webertherm XP a specially designed mineral one-coat render that can be machine pumped for fast-track installation.

The system selector delivers quick specification support based on project requirements, such as thermal performance, reaction to fire, insulation and the final finish.

The tool also offers in-depth information and knowledge on a number of relevant regulations and standards, bringing added assurance for delivering compliant EWI for higher risk buildings, retrofit, and carbon net zero-ready new build homes.

Lee Lambley, technical director at Weber, said: “In developing our system selector, our research showed 78% of architects value easy access to specification information without having to log in. The system does just this, offering a self-serve solution while retaining the option to speak to Weber directly for further advice around additional performance requirements specific to certain projects, such as high-rise buildings.

“Our new façade specification tool navigates the intricacies of performance including fire and associated building guidance and regulations in a timely manner.”

The system selector, working in tandem with Weber’s U-value estimator, gives information on thermal performance to illustrate whether the solution meets the minimum/back stop values for an external wall U-value required under Part L 2023 of the Building Regulations 2022. This also supports delivery of retrofit projects under the PAS 2035 whole-house retrofit standard, and PAS 2035/2030:2023, in place from end-March 2025.

Evergreen Architects, based in Anglesey, North Wales and The Wirral, delivers Passive House new builds and extensions, as well as a significant number of retrofit projects for existing homes where EWI is needed. The firm has been working with Weber to test and provide feedback on the new tool.  

Jonathan Huthwaite, Evergreen Architects director, said: “The use of EWI has increased significantly in the last three years so having a tool that can show a 3D visualisation of the solution in its entirety is a nice touch. Especially when used alongside the Weber U-value calculator to find out what thickness of insulation is required. This convenient tool means we don’t usually need technical support at the early stages of the design process.

“That said, we appreciate having support available for more specialised information, such as condensation risk calculations for complex retrofit projects, which are essential when you’re working with old stone cottages and homes in exposed coastal locations.”

The tool guides users through a series of six questions asking the substrate type, required thermal performance, reaction to fire classification, and insulation type. It includes other special requirements such as faster application time or whether the building is 11+ metres in height, and finally questions the finish required, such as brick, scraped, or dry dashed.

The specification clauses generated can be downloaded or directly added to construction product specification using NBS Source and NBS Chorus. Meanwhile, the option to discuss project requirements with a Weber expert is still available for customers looking for additional information and guidance.

Lee Lambley added: “Part of the thinking behind the system selector was that it would also support the pace and scale needed to meet the UK’s retrofit challenge. The Government’s Build Back Greener strategy estimated 1.5 homes will need to be retrofitted every minute to meet Net Zero 2050.”

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