Chris Stanley, Housing Manager, Concrete Block Association
Although the 2020 news agenda has been dominated by COVID-19, the global Pandemic and the socio-economic impact of attempts to contain and curb it, we must not lose sight of persistent environmental issues.
Although climate change concerns have taken a back seat over the last six months, we must continue to build on the positive work which has been done over the last decade. Our 2050 net-zero carbon targets remain in place, and UK business and industry have an important role to play in our efforts to achieve them, Coronavirus or otherwise.
Housebuilding remains one of the largest net contributors to global emissions. Despite plenty of good intention, some suggest the sector’s not moving fast enough in its efforts to decarbonise, especially when looking to reduce a completed home’s operational costs.
We, building product manufacturers included, are all responsible for change and need to look holistically at how we can design, build and deliver more sustainable homes.
Prompted by recent changes to Part L of building regulations, one method which is gaining popularity amongst specifiers is the ‘Fabric First’ approach. Essentially, this means using specific materials to optimise thermal performance, reducing the need for artificial temperature control which damage the environment through excessive energy use.
It’s an opportunity for UK Housebuilders to adopt greener working practices, and one they must take. But where to start? Cutting through the noise, here are a practical few methods and effective systems to consider when approaching your next development.
Clever structural design and energy-efficient materials are core to energy conservation. This means specifying a high-performance system, such as a traditional cavity wall which will reduce the need for mechanical heating and cooling.
This can be further enhanced by specifying materials with a high thermal mass, alongside appropriate insulation and triple glazed windows. The combination will allow buildings to absorb heat during the day and release it through passive ventilation overnight, lowering homeowner reliance on expensive HVAC systems.
The Tighter, the Better
Better insulation within floor, wall and roof elements has helped UK homes become more energy efficient over the last 25 years, however, improved air-tightness with the construction has also made a significant contribution. Importantly, air leakage rates are reduced through more accurate detailing, eliminating any gaps and cracks in the building fabric, however small.
Thermal bridges remain a common concern and, in my opinion, occur too often. These phenomena hint to poor or careless wall construction and can cause up to 30% heat loss.
However, regulatory changes and our free to download Thermal Bridging Details will no doubt improve consistency, reducing the risk of thermal bridging within the fabric.
An optimum air change rate is required to regulate air quality and moisture control, so it’s important to consider ventilation. Installing a passive system will further reduce energy consumption and deliver better air quality.
Natural ventilation is a principal goal within the design process, of course; sometimes it’s not an option. However, several low-impact solutions are making their ways onto the market, including High-performance controlled ventilation or mechanical heat recovery ventilation (MHRV).
These help minimise waste by reducing the amount of energy thrown away with extracted air, and can be made even more effective when combined with smart control systems to manage their use.
It’s well known that solar gains are an effective way to heat a building passively, especially in cooler climates. Essentially the structure is gradually warmed by the sun’s rays, either directly through an opening, or indirectly through the envelope.
Striking a balance is important, too much solar gain causes overheating, too little and you have to resort to excessive use of wasteful mechanical heating systems. As such, the orientation of the home, and the building products used, need to be carefully planned and researched to prevent either situation occurring.
Fortunately, Part L changes will help, with restrictions placed on particular materials to limit the likelihood of ‘over’ or ‘under’ heating.
Manufacturers Step Up
Of course, housebuilders and developers will be as keen as the specifier to know the carbon footprint of the products they use, and that these materials are produced with net-zero targets in mind.
Manufacturers, particularly in the concrete block industry, are acutely aware of their duty to mitigate climate change. Across the board, we have already undertaken drastic changes to our processes, plants and supply chains to make our materials as carbon neutral as possible.
For example, since 2008 our members have already achieved a 13% reduction in carbon intensity. This means a locally-produced, high-performance, energy-efficient product with strong, sustainable credentials, perfectly positioning our members to remain at the top in a ‘Fabric First’ world.
Whilst some believe the changes to Part L have not gone nearly far enough, it is reasonable to expect that this small step is one of many to come, growing larger each time. Housebuilders need to embrace the new landscape and adopt this ‘Fabric First’ approach. It’s not just a long-term win for the environment, but also the manufacturer, the builder and, ultimately, the most important person of all, the homeowner or occupier.