VIEWPOINT
NET ZERO: THE CHALLENGE FOR MERCHANTS AND HOUSEBUILDERS
Kealan Hunt, commercial director of Tarmac’s blocks business, explores the impact of recent regulatory change in the housebuilding sector and how merchants can support their customers to build for a net zero future.
AS THE UK strives to reach its ambitious net zero targets, the housebuilding sector will have a crucial role to play. Energy use in homes currently makes up 23% of the UK’s greenhouse gas emissions – more than double the amount from agriculture and nearly as much as all transport emissions. The UK can also lay claim to the oldest housing stock in Europe with a typical home here in the UK cooling three times faster than Norway or Germany.
Changing regulations The housebuilding sector has faced much uncertainty and change in recent years – but sustainability has, arguably, remained the one consistent theme. The roll out of the updated Part L Building
Regulations in June 2023 marked an important step in the ambition to build healthy, energy efficient and climate resilient homes. Central to the new regulations is a ‘fabric first’ approach: opting for high performance, efficient products that minimise energy use. The building envelope lies at the heart of this new thinking, with a ‘built tight and ventilate right’ mindset aiming to ensure a cost-effective way of saving carbon and delivering energy efficiency.
Indeed, Part L marked the first transitional step towards the introduction of the Future Homes Standard in 2025. New homes built under this standard must produce 75-80% less carbon emissions than those built under current regulations. Crucially, too, homes will be ‘net zero ready’ and “future-proofed with low- carbon heating and world-leading levels of energy efficiency.”
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Thermal bridges The new Part L guidance focuses on areas such as enhancing U-values, maximising airtightness, optimising insulation and eliminating thermal bridging, the latter of which occurs when an area of a building has significantly higher heat transfer than the surrounding parts.
To limit thermal bridges occurring, the new regulations advise that “opportunities should be considered to use products that help to reduce thermal bridges. Options include… masonry construction: lightweight blockwork in the inner leaf of a cavity wall or both leaves of a party wall can help to reduce thermal transmittance, particularly at junctions, such as the ground floor to wall junction.” The document also advises that, wherever possible, blocks below
the damp-proof course should be the same as those specified in the design for the above-ground main wall element. This is known to reduce the occurrence of thermal bridges.
Aerated blocks are an alternative to traditional dense and medium dense concrete blocks and make compliance with Part L more achievable. Tarmac has refreshed its Durox and Toplite aerated blocks to support builders in complying with the new regulations. For project teams, specifying lightweight aerated blocks offers quicker build times and reduced costs. It’s also worth noting that excessive water absorption usually leads to a loss in thermal performance – with his in mind, our Mortar business is developing advanced products to reduce moisture ingress into cured mortars.
Building for the future A study conducted by The Housing Forum’s Future Network found that the industry is unlikely to meet the Future Homes Standard requirements by 2025 and one in five surveyed admitted to lacking a comprehensive plan to build homes that align with the 2025 emissions objectives. A member of the forum responsible for carrying out the research noted that the results “… show a fundamental lack of understanding of the technologies that developers can adopt to meet their targets. There also seems to be a lack of urgency to increase that understanding and to begin preparations in earnest.” The challenge is huge. But so, too, are the opportunities for merchants. Supporting your customers, helping them to embrace this fabric first approach and going beyond simply meeting Building Regulations will help them prepare for the challenge of further regulatory change from 2025. BMJ
www.buildersmerchantsjournal.net October 2023
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