Do I need planning permission for a loft conversion?
If you live in a flat or maisonette you will not need to apply for planning permission to expand the accommodation within the roof space unless you will be providing a dormer window or inserting rooflights.
If you live in a house a loft conversion for your home will be considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:
A volume allowance of 40 cubic metres for terraced houses.
A volume allowance of 50 cubic metres for detached and semi-detached houses.
No extension should extend beyond the plane of the existing roof slope of the principal elevation that fronts a highway.
No extension should be higher than the highest part of the roof.
Materials used should be similar in appearance to those used on the existing house.
No verandas, balconies or raised platforms are permitted.
Side-facing windows must be obscure-glazed and any opening part to be 1.7m above the internal floor level.
Roof extensions are not permitted development in conservation areas.
Roof extensions, apart from hip to gable ones, should be set back at least 20cm from the eaves.
You will need planning permission for dormer windows if:
A rooflights or skylight will not normally need planning permission unless:
it projects more than 150mm from the existing roof plane;
any part projects will protrude above the highest part of the roof;
you live in an Article 4 Direction Area.
Additional Points
You may need to apply for planning permission if you live in an Article 4 Direction Area. Please refer to leaflets "Article 4 Direction, A Householders Guide to the Legislation".
Even if you live in a relatively new property, such as the Napsbury or Hill End/Cell Barnes Lane developments, it is possible that permitted development rights have been removed by a planning condition imposed upon your house before it was built and you may need planning permission. The history of your property must be checked before undertaking any external alterations, in order to determine whether your permitted development rights have been removed.
If your home is a Listed Building you will need Listed Building consent.
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