Bradley Hirst, Technical Services Manager at Knauf Insulation, explains what housebuilders will need to do to meet the requirements for photography in the new Building Regulations England Part L report.
The 2023 updates to Approved Document L (Conservation of fuel and power) introduced measures to improve the energy efficiency of new homes and there’s a lot for housebuilders to be aware of. As well as a 31% reduction in operational carbon emissions and tighter limiting U-values, the updates introduced a new Building Regulations England Part L (BREL) report.
The changes to Approved Document L aren’t just about reducing carbon emissions on paper. Measures like the BREL report also aim to close the ‘performance gap’, which describes the difference between how buildings are designed to perform and how they really perform once built.
Introducing the BREL report
Housebuilders must now produce a BREL report to demonstrate how a finished build complies with Building Regulations’ energy efficiency requirements. It is produced in two parts, compiled at different stages of the construction process. The design stage BREL report shows how the specification will meet its target rates, then the as-built BREL report shows how the target rates have been met.
The as-built BREL report needs to include images taken during key stages of construction, that show thermal continuity, quality of insulation, airtightness and building services. Simply put, auditors need to see that the insulation has been installed correctly, with minimal air gaps.
Photographic evidence
Photographs of specific details of the foundations and substructure, external walls, roofing, openings, airtightness details and services, such as pipework and ductwork will need to be taken. The pictures must be taken before the works are closed. Usually, one image of each detail will be enough, but some applications (for example smaller details) might require an additional close-up. Anyone can take the photographs, using a digital camera, mobile phone, or tablet, but they need to be of a high enough resolution to see details clearly.
Certain information also needs to be included with each image, such as a geo-location, date, and time stamp. So, make sure the camera has these features turned on when taking the pictures.
Demonstrating quality and continuity
Remember, the photographic evidence needs to show that your insulation has been installed correctly. Air gaps can reduce thermal performance, so it’s important to demonstrate that these have been minimised. One way to do this, is to choose insulation that’s easier to install correctly, such as mineral wool.
Mineral wool insulation is flexible, which allows it to adapt to minor imperfections in the substrate, maintaining close contact and minimising gaps. But the same can’t be said for all types of insulation. Rigid boards, for example, won’t adapt to the wall of a cavity unless it’s perfectly uniform and flat (which is rare). They also need to be cut to size and joints must be taped with precision, leaving plenty of opportunity for human error.
At scale, housebuilders have many options available to them for insulating cavities. Blown-in insulation can be made of many materials, including glass mineral wool, and is ideal for filling cavities or voids around penetrating services, ensuring a complete fill that reduces air gaps and thermal bridging. Prior to installation, your photos will need to show clean cavities and brick ties, as well as very limited mortar droppings.
Continuity of the insulation is crucial for preventing thermal bridging and consequent cold spots, rot or damp. Photos will need to be taken to demonstrate continuity of the perimeter edge insulation at the ground floor level, the external door threshold and below the damp-proof course. Continuity at the ground floor to wall junction and penetrating elements will also need to be recorded, and the same approach will need to be taken for the roof, looking at the joists and eaves.
To help your homes meet the requirements of the BREL report, use insulation that is easier to install correctly and ensure you document it with clear photographic evidence.
Learn more in Knauf Insulation’s Photographic Evidence FAQ and access more free resources on Approved Document L at the Housebuilders Hub.