Building with a quality, high-performance material like aircrete can help you to ensure your self-build meets building regulations. Read on to find out exactly how, from Part L to Passivhaus.
Part L of the building regulations sets the standards for energy performance for new and existing homes. In 2021 changes to the regulations put more emphasis on the performance of the building fabric and minimising the impact of thermal bridging.
A thermal bridge or, cold bridge, is an area in the building envelope which allows heat to pass through more easily. This commonly happens where there is a gap in the insulation layer or where an element such as a joist penetrates the construction.
As we insulate buildings to a higher level, thermal bridges can become a significant source of heat loss, accounting for as much as 30% of total losses, compromising the energy efficiency of a house.
Using aircrete can significantly reduce the thermal bridge effect at junctions, as it has better thermal resistance than dense materials. Moreover, the 2021 amendments to Part L made recommendations regarding building fabric, suggesting the same material should be used to build the foundations and external walls. Aircrete can be used in both foundations and external walls with H+H Foundation Blocks offering self-builders a simplified groundworks solution. See where you can use aircrete.
In 2025, the Future Homes Standard will tighten regulations for homebuilding requiring a reduction of 75-80% in carbon emissions over 2021 standards. Celcon Blocks have been used to build homes to this standard proving them to be a resilient product for use in future homes.
Meeting building regulations and having your home signed-off by building control can seem like a daunting task, but building with Celcon Blocks can help make it just that bit easier.
Self-builders should engage with a Standard Assessment Procedure (SAP) assessor as early as possible in the construction process. SAP calculations are a requirement for new build homes, conversions and extensions in the UK. It’s the government’s method for calculating the energy performance of dwellings.
Accredited assessors generate SAP calculations based on your house design, the minimum standards for which are set out in Part L of the building regulations. This factors in heat lost from junctions and thermal bridges. A final SAP calculation is submitted to building control by the assessor reflecting what has been built. If construction has strayed too far from what was designed, a new SAP calculation may be generated and could show your home is not compliant with Part L.
How to avoid this? Consult an assessor at the design stage of your home as they can advise you on exactly what you need to do to meet Part L. Following this advice from the get-go and checking build quality regularly is essential to ensure suitable evidence can be submitted to demonstrate that your self-build complies with the building regulations.
H+H offers free resources useful for anyone building with its aircrete products that can help self-builders along in this process.
Interest in Passivhaus construction has been steadily increasing in the UK due to the ultra energy efficient nature of Passivhaus homes. Passivhaus, sometimes referred to as Passive House, is a building standard devised by the Passivhaus Institute in Germany.
The standard is designed to create exceptionally thermally efficient, airtight homes that reduce or eliminate the need for additional heating and incorporate a mechanical ventilation system. This saves homeowners money and drastically reduces a house’s operational carbon footprint.
Due to their inherent thermal properties, Celcon Blocks can be successfully used in the construction of Passivhaus homes. With the right insulation materials, aircrete cavity walls can reach a U-value as low as 0.11W/m2K to easily meet Passivhaus Standards. Typical Passivhaus external walls have U-values between 0.1 and 0.15 W/m2K.