Minimum ceiling height loft conversion

[Strak]

Hello all,

 

We're currently finalising some extension plans for our house, and I'm a little confused over the official requirements under UK building regs for minimum ceiling height in loft spaces.

 

The loft area will consist of bedroom, bathroom and stairwell - stairwell clearance height is 2 metres, and the ceiling height under the roof ridge will be approx 2.15 metres. I know the minimum height over the stairwell is 2 metres, but have read conflicting information over the minimum ceiling height for the rest of the loft. Many websites I found state that building regs require a minimum of 2.2 metre head clearance in the loft bedroom, but I can't find any official reference to a building regs approved document where anything other than height over the stairs is a requirement.

 

I'm coming round to understanding that the 2.2 metres comes from a recommendation somewhere, rather than an official requirement, but am writing this post to double check. I believe that this website (

What’s the UK’s standard ceiling height for houses, extensions and loft conversions? (designsindetail.com) describes the actual situation: 

  Quote

 

There is no minimum ceiling height requirement for home extensions and loft conversions in the UK. Building regulations, however, state there needs to be at least 2 metres of head room above stairs, reducing to 1.8 metres in some situations.

If you are building a new house, planning legislation will determine the minimum floor-to-ceiling height. In most parts of the UK, it is set at 2.3 metres. In London, it is 2.5 metres.

For a home to function properly, it should meet acceptable standards and be fit for purpose.

The average ceiling height of a house in the UK is around 2.4 metres.The optimum ceiling height for a house is between 2.6 to 3 metres – a standard used by Victorian house builders to ensure good levels of natural light and ventilation.

If you are building an extension, the ceiling should be at least the same height as the existing rooms in the house, whenever possible.

A reasonable ceiling height for a kitchen extension is about 2.3 metres. If planning rules restrict the building height, lower the floor to gain extra headroom.

Loft conversions should be no lower than 2.1 metres over half of the floor area. 2.3 metres is about standard for a loft bedroom.

 

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Again, as far as I understand, the last part mentioning 'no lower than 2.1 metres over half of the floor area' is not an official regulation.

 

I'd really appreciate it if somebody could help to confirm the above, or if incorrect point me to the approved building regs doc and section that I need to look at.

 

Many thanks!

[Mike]

  On 08/04/2024 at 21:11, Strak said:

the last part mentioning 'no lower than 2.1 metres over half of the floor area' is not an official regulation.

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Correct, at least in England. There was once a minimum room height, but it was removed from the regulations many years ago.

[DevilDamo]

There isn’t a minimum. With standard internal doors being 1981mm plus their architraves and external window heads normally being 2.1m above floor level, ideally you want the ceiling to be at least 2.15-2.2m.

[kandgmitchell]

  On 08/04/2024 at 23:14, Mike said:

There was once a minimum room height, but it was removed from the regulations many years ago.

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Those were the days. Regulation K8 Height of Habitable rooms, last seen in the 1976 regulations I believe. This and lots of other stuff (remember zones of open space?) was swept away when the 1985 re-cast of the whole system brought in the Approved Document approach we use today.

 

It set a minimum height of a habitable room at 2.3m. On loft rooms it said:

Provided that, if such room is wholly or partly in the roof of the building, it's height shall be not less than 2.3m over an area of the floor equal to not less than one half of the area of that room measured on a plane 1.5m above floor level.

 

And that was the law - set out in the statutory instrument, non-compliance was an offence. The only way to overcome a shortfall was to apply for a formal relaxation which had a process all of it's own including an appeal to the Secretary of State upon a refusal by the LA.

 

 

[Crofter]

  On 09/04/2024 at 06:45, DevilDamo said:

There isn’t a minimum. With standard internal doors being 1981mm plus their architraves and external window heads normally being 2.1m above floor level, ideally you want the ceiling to be at least 2.15-2.2m.

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You can saw the bottom off a door though 😁

 

We did a loft conversion in our previous house, that was only 2m headroom. Sailed through the building warrant process without a hitch. That was in Scotland, in about 2009, well before this forum existed.

[Strak]

Hey all, just wanted to say thanks for your replies on this - currently working with the architect to try to get around 2.3 of height, but this thread has been really helpful to make sure we don't accidentally build something which would not be classified as a bedroom should we sell the house in the future.

[Movieman]

Another potential option is to lower the floor in the ceiling below