The UK is ramping up to meet the ambitious goal of 1.5 million new homes by 2030. The heat is on to get building, and fast. But such rapid construction brings risks. Because even in brand-new buildings, thermal inefficiency, damp, and mould remain common issues. And much of it comes down to the eaves junction – the join between roof and wall.
Dr. Alex Boote, Product & Innovation Manager at , a leading manufacturer of cavity barriers, closers, and insulation products, shares insights on why this small detail has far-reaching implications.
Overlooking the eaves
On paper, new homes are better insulated than ever, thanks to stricter building regulations and the drive toward net zero. Yet, in practice, studies repeatedly indicate that in-use performance often falls short. Even high-quality insulation can underperform if installed poorly.
The eaves are notoriously difficult to access and properly insulate. But it is also one of the most common areas for heat loss, condensation, and structural decay. Small oversights – like thermal bridging at the eaves – can create or worsen cold spots, reducing the overall effectiveness of the insulation, driving up heating costs, and leading to damp, mould, and serious health risks.
That’s why we developed the Eaves Insulator: a simple solution to insulate and ventilate this critical detail, reducing the risk of thermal bridging and mould from day one.
How the Eaves Insulator works
Traditionally, this junction between the wall and roof is filled by manually packing mineral fibre wool into the hard-to-reach eaves gap. This approach leads to inconsistency, as it’s difficult to measure the right amount of material or apply the correct level of compression, resulting in uneven coverage and reduced performance.
ARC’s Eaves Insulator is pre-assembled and designed for simple installation. Made from non-combustible glass mineral wool and a patented ventilation tray, it combines insulation and ventilation, maintaining the required 25,000 mm² airflow while ensuring a continuous thermal barrier. Its design allows it to flex and fit into tight, awkward spaces, adapting to various roof pitches.
Once positioned, it forms a snug fit, maintaining both insulation continuity and proper ventilation without extra tools or guesswork. In turn, this helps improves the SAP rating in newbuilds, reducing heat loss through the wall plate junction by up to 49% when compared with traditional loft insulation.
Retrofitting: the other half of the solution
While new builds are a key focus, it’s important not to lose sight of the millions of existing homes that remain unfit for purpose. According to a recent English Housing Survey, over 6.6 million homes in England fail to meet required living standards.
Retrofitting presents an opportunity to raise living standards, cut emissions, and reduce energy costs – especially in social housing and older properties. We continue to support this through our range of retrofit products, helping to close the performance gap not only in what we build tomorrow, but in what already stands today.
For more information, visit: retrofit for warm safe homes – ARC Building Solutions
