Getting External Wall Insulation (EWI) Right at the Roofline with SWIGA

External Wall Insulation (EWI) is a game-changer for improving energy efficiency in retrofitted homes, but it hasn’t been without its challenges. Persistent failures with outdated roofline detailing led to significant changes in industry standards, with PAS 2035 banning the use of eaves and verge trims. This move has sparked a shift towards better-quality solutions that deliver long-term performance and energy savings.

Why PAS 2035 Banned Eaves and Verge Trims

The decision to ban eaves and verge trims was driven by repeated failures that stemmed from:

• Poor-quality components: Cheap materials often failed prematurely, jeopardising the entire system.
• Generic, non-specific detailing: One-size-fits-all approaches didn’t account for the unique requirements of individual properties.
• Over-reliance on mastic seals: Mastic was often the only line of defence, which wasn’t enough to prevent issues like water ingress.
• Inadequate training and supervision: A lack of skilled oversight led to poor installation practices.
• Built-in thermal bridges: These flaws undermined the very purpose of EWI by allowing heat loss and compromising energy efficiency.

Extending Rooflines: The Best Solution Success

Extending the roofline above EWI is widely regarded as the best technical solution to avoid these issues. By eliminating thermal bridges and providing a durable, weather-tight finish, roofline extensions ensure the performance and longevity of EWI systems.

However, the higher costs associated with this approach have limited its adoption, particularly in properties like mid-terrace houses. Despite available funding, many homes were left uninsulated, creating a gap in the market that needed addressing.

A New Era: PAS-Compliant Roofline Closure Systems

In response to these challenges, the Solid Wall Insulation Guarantee Agency (SWIGA) has developed new roofline closure systems that meet PAS 2035 standards. These innovative solutions aim to overcome the limitations of traditional trims while ensuring long-term performance and compliance.

A recent discussion featuring Dr Peter Rickaby, former technical editor of PAS 2035, Andrew Champ, SWIGA’s Chief Executive, and Jeremy Ritchings from PermaRock, delves into this new approach. Over the course of 3 ½ years, the industry has collaborated on research, development, and testing to create robust solutions that address the shortcomings of previous systems.

Dr. Peter Rickaby

Andrew Champ

Jeremy Richings

Key Takeaways from the Discussion

The conversation highlights how the new systems resolve the issues raised in the Hansford and Bonfield Reviews, ensuring lessons from the past are not repeated. Key advancements include:

• Robust designs: High-quality materials and well-engineered details eliminate the need for unreliable trims.
• Thorough testing: Rigorous trials in real-world conditions guarantee durability and performance.
• Improved training: Installers are now better equipped with the skills and knowledge to ensure correct implementation.
• Seamless integration: The new systems work as part of a whole-house retrofit, enhancing overall energy efficiency.

Why this matters

These updated roofline closure systems are a major step forward for the industry. They not only comply with PAS 2035 but also make EWI more accessible and reliable, even for challenging property types. By addressing thermal performance, durability, and weather resistance, these systems support the UK’s broader mission to retrofit its housing stock and reduce carbon emissions.

Watch the Full Discussion

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