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Welsh Government publishes Non-Domestic Building Regulations


Last week, the Welsh Government released the next version of Building Regulations and Approved Documents F (ventilation) and L (conservation of fuel and power) for non-domestic buildings. The new approved documents have been released following a lengthy consultation period and are due to come into force on 29th March 2023.

The release of these documents marks the first significant change to welsh building regulations in nearly a decade. These new standards will ensure that building work moving forward will deliver a better standard of living when it comes to health, safety and energy efficiency. This will go some way in helping Wales to reach its aim of getting the country to net zero by 2050.

Following the release of the new approved documents, Elmhurst has identified some of the significant changes that will be introduced come March next year:

  • There will be a 28% reduction in carbon emissions in new buildings compared with Part L 2014 standards
  • A Primary Energy compliance metric has been introduced alongside the existing carbon emissions standard
  • Incentivise new heat networks to be low carbon
  • Tightened limiting fabric standards for thermal elements (i.e walls, floors, roofs, windows)
  • Uplift to minimum standards for building services for new and existing non-domestic buildings, and including them within the approved document rather than having the non-domestic building services compliance guide (NDBSCG)
  • Adoption of CIBSE TM 23 which allows for either Pulse or blower door testing as methods to determine airtightness.
  • Overheating risk has been addressed in its own approved document (Part O) and is no longer featured in Part L
  • The SBEM v6 methodology will be adopted as with England and Scotland – We are currently waiting on the new version to be released by BRE, we have been informed it is expected to be December.


Elmhurst’s Non-Domestic Team Leader, Steve Windmill

“We welcome the new version of the Approved Documents which will improve the energy efficiency of new buildings in Wales. As expected the new standards will commence in March 2023 and we await information from the BRE which will enable us to update our SBEM software, SBEM Online. This will help us start to understand the impact of these new standards.”

Approved Document L

“This approved document takes effect on 29 March 2023 for use in Wales. It does not apply to work on a particular building where a building notice, full plans application or initial notice have been submitted before that date, provided the work for each building is started before 29 March 2024 and it does not apply to sites where a building notice, initial notice or full plans application were submitted before 31 July 2014 and building work commenced before 31 July 2015.”


Other links:

Approved Document Part L – Volume 2 (Buildings other than dwellings): https://gov.wales/sites/default/files/publications/2022-09/approved-document-l-vol-2.pdf

Approved Document Part F – Volume 2 (Buildings other than dwellings): https://gov.wales/sites/default/files/publications/2022-09/approved-document-f-vol-2-final.pdf