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PLANNING RULES from 1 Oct 2008

Permitted Development   

A planning application is not normally required for loft conversions. Most can be carried out as ‘Permitted Development’ subject to complying with the rules below.

The new rules are similar to the previous regime. As before,  dormers are generally permitted to the rear, but not to the front. However, the rules are now more relaxed about side dormers, unless the side of your house happens to face a highway.

Conversions with just skylight roof windows shouldn’t be a problem, as they don’t extend ‘beyond the plane of the existing roof slope’. But converting hipped side roofs to gables is a material alteration that still requires planning consent.

The main grey areas concern how exactly you define the terms ‘ principle elevation’   and  as far as practicable’ – see below.

If your design doesn't meet the following rules, you can of course apply for planning permission.


No dormers (or other roof extensions) are permitted to the front. This applies where the front of the house is  “the principal elevation that fronts the highway”.


If you’re just adding skylights to your roof, there will be no increase in the size. Dormers (and other roof extensions) are still subject to the same generous volume limits. So unless your house already has a roof extension that’s eaten up this allowance, it should easily comply:-

                              40 cubic metres for terraced houses

50 cubic metres for detached and semi-detached houses.

In terms of height no dormer (or other roof extension) must be taller than the highest part of the existing roof.



Dormers    must be set back at least 200mm from the eaves, as far as practicable.  

Materials   should be similar in appearance to the existing house.

          No balconies, verandas or raised platforms – including roof windws with ‘fold-out balconies’

Windows     - side-facing windows to be obscure-glazed.

       - any openings must be 1.7m above floor level.


CONSERVATION AREAS (and other ‘designated land’*)

Dormers and other roof extensions are not permitted



              None permitted - but you only need make a single application for Listed Building Consent




* "original house" =  as it was first built or as it stood on 1 July 1948

* Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.


  Click here to see new planning rules demonstrated live' on the  interactive house


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