Loft conversions: When is a building regulations application needed?

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Image of timbers in a roof

When you’re contracted to carry out work in a loft area it’s important to know whether or not your project will be controllable under the building regulations and therefore require an inspection from building control. You must be aware that there are lots of building regulations that apply to loft conversions, particularly to do with fire safety and thermal insulation. Failure to get approval for loft works can lead to enforcement against the builder or owner and can leave the owner uninsured and unable to sell their home.

If your project involves adding a permanently fixed stair or fixed ladder, installing a floor or lining walls/rafters then the works are considered to be a loft conversion and an application will be required, irrespective of the proposed use of the room. The key thing to consider is: if it looks like a room – it’s a room.

Structural alterations to an existing roof such as removal of purlins or struts, as well as the installation of rooflights, require building regulations compliance because the works are considered to be a structural or material alteration.

However, you don’t need to put in a building control application if your project only involves the installation of power and/or lighting to the roof space as long as an electrician registered with a government-authorised competent persons’ scheme such as NAPIT or NICEIC carries out the work.

Read: Building a loft conversion

Key points to consider when carrying out a loft conversion

  • Means of escape must be carefully considered, particularly where converting a loft to an existing house. This usually requires the provision of fire doors to protect the staircase and always requires the installation of a mains-wired fire alarm system.
  • Where the staircase comes down into an open plan layout at ground floor it causes means of escape issues that may require an additional escape route or the provision of sprinklers.
  • When looking at an alternative escape route ensure it is separated from the main staircase.
  • When you propose a solution other than a fire-protected stair direct to an external door it is critical to seek early consultation with building control to discuss the proposed solution.
  • Note that installing boarding over your loft insulation will compress the insulation and seriously reduce its energy saving properties, so give consideration to prevent this issue arising.
  • It is critical that there is enough headroom, and this may affect the viability of the project. Two metres are required above the stair and the landing: when calculating this, ensure you have allowed for the additional depth of floor joists and the lowering of the ceiling by additional insulation.
  • You may need to make a separate application for planning permission. Contact your local planning office for advice if unsure.

Further information on loft conversions

Read our loft conversion guide and our technical guidance on Loft conversions in two-storey houses [withdrawn for updating 21/8/20).

If you’re unsure about any aspects of building work then please consult your local authority building control team, who will be happy to advise you. Use our free postcode search tool to find your local team.


Please Note: Every care was taken to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgement. It is the responsibility of the dutyholder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.



Submitted 3 years 10 months ago

Have read your interesting guidance on loft conversions in 2 storey houses but slightly taken aback by requirement set out in para (b) on existing doors of historical or architectural merit having hinges with a melting point of 8000 degrees C. I think you mean 800.
Kind Regards


Submitted 3 years 10 months ago

Thanks for pointing this out. We will amend the document and re-upload it later today.

Kind Regards,


Loft conversion guide and technical

Submitted 3 years 10 months ago

All it says is page not found...

Building Regs for a Loft Conversion

Submitted 1 year 8 months ago

If I were to build a loft conversion does it need a radiator installing to meet any Building Regs requirement? I cant see that a radiator (or any other form of heating) is needed to satisfy any building Regs requirement

Loft conversion

Submitted 1 year 6 months ago

I've put beams in and started to floor the loft ready for it to be used as storage space . However my wife has now asked if we could have it fully converted into a living space . What regs or permission would I need ? .
Thinking velux windows , insulated roof and walls and a staircase although this maybe the hardest thing to sort


Submitted 1 year 6 months ago

Hello there

Thanks for leaving your comment.

You can find some information on converting your loft and the permissions needed on this page:

Kind regards
Julie, LABC

(No subject)

Submitted 1 year 5 months ago

I read your valuable suggestions on upper-floor loft conversions. This is great.

Loft conversion

Submitted 1 year 5 months ago

I have 2 bedrooms terrace house, so thinking loft open for a room, I want insulation sky window staircase, simple heating and electric plugs and lights. so, do I need the planning permission ? I'm from Aylesbury .


Submitted 1 year 5 months ago

Hello there - thanks for leaving your comment.

There is some information on planning permission for loft conversions here

If that doesn't answer your query, please contact your local planning authority to check.

Kind regards
Julie, LABC

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