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Permitted Development   

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

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, since they don’t extend ‘beyond the plane of the existing roof slope’. But converting hipped side roofs to gables is a material alteration that 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 subject to very 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 should 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 windows with ‘fold-out balconies’


– side-facing windows to be obscure-glazed.

– new window openings must be 1.7m above floor level.


CONSERVATION AREAS (and other ‘designated land’*)

Dormers and other roof extensions are not permitted



All works are subject to applying for Listed Building Consent


More detailed information about Planning Permission