New Part L Building Regulations – What does this mean for your rooflight installation?

What is “Part L”?

Part L is an English building regulation which sets parameters and standards for energy efficiency and performance for new and existing buildings.

Part L first came into force on 6 April 2014, but on 15 June 2022, an update of the regulation was implemented, stating that all new buildings completed from that date onwards had to produce at least 31% fewer carbon emissions than previously accepted.

For buildings that were still in the planning process on 15 June 2022, a 12-month grace period was permitted. This meant that if a building notice – or initial notice – had been applied for pre-15 June 2022, the project would be considered under the previous Part L regulations so long as the building work began before the end of the grace period – 15 June 2023.

What does this mean for me now?

From now on, anyone involved in developing buildings in England must comply with the new energy performance standards and carbon dioxide emission reduction targets for both new-build and existing projects. For new domestic buildings, that target is 30%, while new commercial buildings have a slightly lower target of 27%.

As well as hitting the reduction % targets for carbon dioxide emissions, under the new regulations:

Walls, windows, rooflights and doors must comply with the Part L regulations.

New homes will be assessed against Standard Assessment Procedure (SAP) 10, which replaces SAP 2012 and sets higher insulation requirements.

During each phase of a building project, professionals such as builders and developers will have to provide photographic evidence of how their project is adhering to standards.

Developers won’t be permitted to complete a project without a compliant SAP10 BREL report.

EOS Rooflight Installation Skylight replacement with insulated upstands

What does this mean for me in the future?

The uplift to Part L requirements is just one of many changes which will impact the building industry in the coming years.

The Future Homes Standard – which is expected to be implemented by 2025 – will set out even stricter energy efficiency standards for new residential buildings. It will sit alongside The Future Buildings Standard, which will set tougher targets for non-domestic buildings, as part of the government’s two-step overhaul of building regulations in England.

Both current and future changes to regulations aim to ensure that all new homes create only around a quarter of the carbon emissions previously seen with houses built under the old rules. Eventually, it’s hoped that a reduction of 75–80% will be achieved.

How can I ensure my project – including my rooflight – complies with Part L?

Using the ‘fabric-first’ approach – and considering all the tiny details – before a brick is even laid is the best option.

The fabric-first approach means you give extra consideration to the building’s fabric – that is, the physical elements (frames, insulation, windows, floors, doors, roofs and, of course, rooflights which separate the inside environment from the outside – to prioritise heat conservation right from the start of the project.

This extra attention to detail and consideration of using high-quality materials and suppliers should result in a compliant project.

To ensure compliance, we recommend you buy your upstand from the same supplier as your rooflight (like us!).

Could a non-compliant upstand mean my project isn’t signed off by building regulations?

In a word, yes.

As we mentioned earlier, regulations don’t just apply to the building itself: structural assets such as walls, windows, doors and rooflights must comply with the required U-value. And for your rooflight to be compliant, your upstand must be too.

Non-compliant rooflights would certainly increase the likelihood of a project failing to be signed off by building regulations.