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Has Cardiff jumped the gun by announcing Part L go live dates?

02 Dec 2020


Since the UK Government announced plans to introduce a Future Homes Standard, or, as the papers like to call it, the ‘gas boiler ban’, the three most common questions we’ve been receiving are:

Are they actually banning gas boilers?

When are these regulations coming into force? And,

How long a grace period will we have on existing building sites?

On that first question, no, they’re not banning boilers. See our other articles for a more in-depth answer.

On the other two questions, after a year of speculation, we may finally have some answers… not from Westminster, but from the Senedd in Cardiff.

Last week, the Welsh Government announced a new consultation to change Approved Document Part L1b (energy use in domestic conversions and extension). They also added extra details to the proposed changes to AD F (ventilation of existing buildings), and set out plans to introduce a new overheating building regulation (AD S).

Within this flurry of paperwork, they set out targets for implementing these new updates to Building Regulations, along with the highly anticipated SAP10 and AD L1a launch.

Before we get to the big reveal, we have two caveats. 1) This information is currently open for public consultation so is subject to change. 2) This applies to Wales only, but traditionally England and Wales launch AD L changes at the same time.

Go Live

The Welsh Government intends to publish the updates for AD L1 (energy use in dwellings), SAP10 (new methodology which encourages heat pumps over gas boilers), AD F (ventilation in dwellings) and AD S (overheating) in the spring of 2021. The ‘go live’ date will follow six months later in the autumn.

AD F2 and L2 (ventilation and energy use in non-domestic buildings) will be released in autumn 2021 with a ‘go live’ date in Spring 2022.

Where a building notice, initial notice or full plans deposit has been submitted to building control after the go-live date, the building work must be designed to comply with the new requirements.

The specific date has not yet been confirmed, but historically we’d be looking at the first weeks of April and October.

Transitional Arrangements

Any site which is registered with Building Control before the go-live date can be built to the current version of building regulations. But – this is a big ‘but’ – there will be a deadline.

The proposals suggest construction sites will have a two year window after the go-live date. After that, any building which hasn’t been started will need to meet the new requirements.

Previous transitional arrangements have been defined per site, so if you registered one site of 1,000 buildings and you started house number one within the grace period, all 1,000 could be built to the old regs.

This new definition will mean fewer homes are built to outdated regulations… If you registered one site of 1,000 dwellings, and two years later you’ve only started 239 buildings, the remaining 761 would need to meet the new regs.

If you’ve been following our articles on the Future Homes Standard, you’ll know how the new targets are expected to bring the biggest leap in energy targets since SAP was first made mandatory. This new method of transitional arrangements will lead to houses on the same street having to meet different regulatory requirements.

You can comment on the Welsh consultation until 17th February 2021:


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Jon Ponting

Energy & Sustainability Specialist


Jon Ponting

Energy & Sustainability Specialist
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