Critical knowledge gaps are stalling building projects and undermining sustainability goals, according to an industry insights session led by Eurocell.

A lack of confidence around building regulation compliance – particularly Parts L, O and E – alongside misconceptions about sustainable materials means UK building projects risk facing a dual threat of costly remedial work and significant delays.

The balancing act of compliance
A key takeaway from the industry workshop was that evolving Building Regulations continue to pose a challenge.

The introduction of Part O (overheating) has raised questions about how it might affect window sizes, and whether its scope might expand beyond new-build dwellings to include major renovations and extensions in the future. For now, its strict requirements apply only to new residential constructions.

While the simplified method within Part O places strict limits on glazing-to-floor area ratios, many specifiers are finding that dynamic thermal modelling is required to maintain larger window designs without failing compliance.

Another point made clear by the session is that UK builders and specifiers are stuck in a balancing act, struggling to meet the demands of different regulations that sometimes seemingly conflict with each other. Parts L and O are examples of this – one demands higher insulation and low air leakage, while the other wants to prevent excess heat from building up.

Furthermore, Part O’s ventilation requirements often clash with the acoustic requirements set out in Part E, especially for projects in urban environments.

To navigate this, Eurocell advises that specifiers can consider a more integrated approach – using a combination of acoustic glazing, controlled ventilation, shading, layout planning and mechanical or passive cooling solutions – rather than viewing regulations in isolation.

Thermal trap
The workshop also revealed that the relationship between insulation and solar gain remains a technical blind spot for many, making it difficult to meet Passivhaus standards. Lowering the U-value to improve insulation generally reduces the g-value as well, as high-performance coatings often block some solar radiation.

Arron Crisp, technical specification manager at Eurocell said:

“Following the Government’s update to the Future Homes Standard, the industry’s now gearing up to meet these elevated requirements. While the pressure is on to adapt to these new benchmarks and the transition from SAP 10.3 to the new Home Energy Model (HEM), confusion remains about existing legislation, specifically the June 2022/23 updates to Parts L and O, which have already been in place for several years.

“We need clear, actionable guidance to avoid the cycle of non-compliant builds, delays and costly redesigns. Builders and specifiers must be brought along on the journey when new regulations are being developed and introduced. Only then will the industry feel confident and truly ready to implement these changes.”

Challenging the ‘plastic is bad’ narrative
Sustainability remains a hot topic, yet the workshop revealed that the industry is still unclear on the sustainability aspects of modern materials like PVC-U.

There’s an old narrative that plastic is bad for sustainability, but this isn’t always the case. The session highlighted that through advanced co-extrusion and up to 10 recycling cycles, the material lifecycle of PVC-U can span 300+ years, maintaining high structural and thermal performance throughout.

Furthermore, PVC-U offers a significantly lower embodied carbon footprint than aluminium, something that will be increasingly vital as the industry moves towards low-carbon home mandates. Furthermore, the mechanical recycling of PVC-U is a significantly less energy-intensive process than the smelting required for recycled aluminium, contributing to a lower initial embodied carbon footprint for PVC-U frames.

Exactly how the age of plastic and its recycling history might be proven, though, remains an ongoing challenge. While exact tracking of individual frames isn’t yet possible, batch-level traceability and mechanical testing can help to ensure material integrity and traceability through recycling loops.

However, there are options that may become more viable in the future – such as digital product passports or embedded QR codes – that will enable the precise tracking of production batches, recycling history and material composition.

With the Future Homes Standard coming into force, Eurocell says its latest consultation highlights the need for clarity and a more collaborative approach to technical education in the sector.

By bridging the gap between regulatory theory and on-site application, the industry can treat Building Regulations and sustainability goals as complementary and achievable goals, rather than conflicting obstacles.