The Part L grace period just ended on June 15th – what you need to be doing now 

Posted: 3rd August 2023

Last year, Part L of Building Regulations, which covers the conservation of fuel and power, was significantly amended. It was the first step towards the Future Homes Standard, which aims to make sure all new homes built from 2025 produce around 75% less carbon emissions, and, ultimately, support the commitment to achieve net zero by 2050.

The new Part L of Building Regulations came into force on 15 June 2022. However, to give the industry time to adapt to the changes, the regulations had a twelve-month grace period. The changes did not apply in relation to building work where a building notice or an initial notice had been given to, or full plans deposited with, a local authority before 15 June 2022. However, this only applied if the building work started before 15 June 2023.

Now that 15 June 2023 has passed, all building work will need to comply with the new regulations without exception or exemption.

What do the new Part L regulations say? 

There are different requirements depending on whether it’s a new building or an existing one. New buildings have more demanding requirements because builders have more control over more of the elements of the building. On existing dwellings, the regulations are slightly less demanding.

In brief, the new regulations are as follows:

In new dwellings, windows and glazed doors (defined as where more than 60% of the door is glazed), must meet a notional U value of 1.2 W/(m²K). You can think of ‘notional’ as being a ‘recipe’ approach that means if all other standards are also met, the building will comply.

In existing dwellings, replacement windows or glazed doors must have a U value of 1.4 W/(m²K).

What do you need to watch out for now the Part L grace period has ended? 

It is important to note that not all window and door systems were able to comply with the new regulations when they changed on 15 June 2022. Several systems have only been upgraded in recent months. Therefore, it is essential to check with your systems supplier that your system complies with the new Part L regulations.

Rest assured that here at Mercury Glazing we only manufacture systems that comply with the new Part L.

A reminder of the updated reporting requirements for Part L 

The way you need to show evidence of compliance to Part L has changed as part of the updates.

For dwellings, a Building Regulations England Part L (BREL) report is needed, along with photographs taken at each build stage to prove that the building work meets regulatory standards.

For buildings other than dwellings, two Building Regulations UK Part L (BRUKL) reports are now required, one for the ‘design’ and one covering ‘as built’.¹

Note the requirement for photographic evidence – if you aren’t already doing this, you will need start taking photographs of installations at every stage. The regulations say:

Photographs should be digital and of sufficient quality and high enough resolution to allow a qualitative audit of the subject detail. Close-up photographs may be needed where a long shot image provides insufficient detail. More than one image of each detail may be needed. Geo-location should be enabled to confirm the location, date and time of each image. Each image file name should include a plot number and detail reference according to the numbers used in paragraph B7. For example, Plot 1 eaves detail would be P1/3b.²

Where to go for advice about Part L 

If you have questions about the new Part L requirements around thermal efficiency, here at Mercury Glazing we are happy to help. We can provide as much or as little technical support as you need with all your installations. From consultation to installation, our team will be with you every step of the way – it’s the Mercury difference!