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Frequently Asked Questions

Do loft conversions need planning permission?

Thankfully, planning permission for loft conversions is no longer needed in most cases.

On 1st October 2008 the planning laws for loft conversions in England and Wales changed significantly. Before then a Total Permitted Development (PD) allowance was granted on a property to allow it to be extended before it would require planning permission: a maximum of 50 cubic metres for a terraced home and 70 cubic metres for a semi-detached. A loft conversion could be constructed up to a volume of 40 cubic metres for a terraced property and 50 cubic metres for a semi-detached before it required planning permission.

These maximum figures still apply to loft conversions. But before the law changed, if you already had a ground floor extension then the volume of the extension would be subtracted from the loft conversion allowance, which meant that in a lot of cases seeking planning permission for attic conversions was inevitable.

What’s more, obtaining permission was always a minefield since different local authorities had different criteria on planning regulations. Under the new simplified planning laws, only a few loft conversions need planning permission.

There are some restrictions with the new planning rules, however:

Loft and roof conversions

  • Must not exceed the highest part of the existing roof (its ridge line)
  • Dormer windows are not allowed to be front-facing a highway
  • There is a maximum volume limit of 40 cubic metres for terraced houses and 50 cubic metres for semi-detached and other dwellings
  • Planning permission must be sought in conservation areas.


  • Materials shall match as closely as possible or be of a similar appearance to those used on the exterior elevations of the existing house
  • Other than in the case of a gable end, the rear dormer of the attic conversion shall not be less than 200mm from the edge of the original eaves
  • Side windows in gable end loft conversions shall be obscure-glazed and either non-opening or have the opening sash positioned more than 1.7 metres above floor level
  • Any other alteration to the roof of a dwelling house must not protrude more than 150mm beyond the original roof plane, or be higher than highest part of the original roof.

For more information on the new planning laws that came into effect after 1st October 2008 governing England and Wales you can view the government’s Planning Portal.

Alternatively, contact us now for a free, no-obligation loft conversion suitability survey and quotation for your home: 01707 658604 or email.

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