New Part L – The first stepping stone to achieving net zero?

New Part L – The first stepping stone to achieving net zero?

The introduction of the New Approved Document Part L of the Building Regulations at the end of 2021 may have gone a little unnoticed at the time, but this amendment is the first step in the long journey the UK has to achieving its target of net zero carbon buildings by 2050.

Unlike its predecessors, Part L is an interim uplift paving the way for the introduction of the Future Homes Standard in 2025, and ultimately to the 2050 targets set by the Government. With an approximate 30% carbon emission reduction against Part L 2013, the new edition not just underpins the fabric first approach, but strengthens it to a degree – however, not quite as far as the industry wanted.

The headlines from the New Part L

Implementation date June 2022 with 1 year transition period allowed for planning applications.

New homes will be measured against four performance metrics:

1. Primary Energy
2. CO2 Emissions
3. Fabric Energy Emissions Standards
4. Minimum Standards for Fabric and Fixed Building Services

Notional dwelling specification for a new dwelling*

External walls including semi-exposed walls | U = 0.18 W/(m²·K)

Party walls | U = 0

Floors | U = 0.13 W/(m²·K)

Roofs | U = 0.11 W/(m²·K)

Limiting dwelling specification for a new dwelling*

External walls including semi-exposed walls | U = 0.26 W/(m²·K)

Party walls | U = 0.20 W/(m²·K)

Floors | U = 0.18 W/(m²·K)

Roofs | U = 0.16 W/(m²·K)

Notional U- Values are a design performance to ensure compliance if all standards are met.  Limiting U-Values are the worst acceptable levels of performance and are unlikely to meet compliance standards.

BREL report

The Buildings Regulations England Part L (BREL) report and photographic evidence should be provided to the building control body and to the building owner to show that building workcomplies with energy efficiency requirements.

Accredited Construction Details (ACDs) will no longer be acceptable and specific junction details should be produced.

Planning authorities will retain the power to set their own targets.

If you would like to find out more about this regulation, then please click on the links below to access the full document.

Approved Document Part L