Loft Conversion Myth Buster – Planning Permission.

This is the first of our Myth Buster series, “Loft Conversion Myth Buster – planning permission”.  If you have any “myths” for us to bust, drop us a line!

MYTH: All loft conversions need planning permission.

TRUTH: A loft conversion is a permitted development, thus not requiring planning permission. However, this is only the case as long as the following applies:

  1. You are not exceeding a volume allowance of 40 cubic metres additional roof space for terraced houses. This increases to 50 cubic metres for semi-detached and detached houses.
  2. Your dormer extension does not go beyond the plane of the existing roof slope of the elevation facing the highway. Essentially, this means that you will need planning permission if you would like to have a dormer at the front of your property.
  3. Your conversions does not go higher than the highest part of your roof. This means that the roof of your dormer needs to be lower than the ridge of your roof.
  4. Your materials should be similar in appearance to your existing house, e.g. bricks, and roof tiles.
  5. Your conversion does not have a balcony, veranda or raised platform.
  6. If you have a side-facing window, it needs to be obscure-glazed, and any opening must be 1.7m above the floor.
  7. You are not in a designated area.
  8. Your dormer extension (except a hip to gable) must to be set back, as far as practicable and at least 20cm from the eaves.
  9. Your conversion can’t extend beyond the outer face of the wall of the original house.

If any of the above do apply to your conversion, you will need to seek planning permission from your local authority.

Further Information

You can find more information and technical guidance here. Did you find our “Loft Conversion Myth Buster – Planning Permission” useful? Then keep and eye out for our other Myth Busters coming soon!

If you don’t need planning permission, and you’re ready to go with your loft conversion, you can read our blog about concept and design for some more information.

Should you have any questions, you can chat to a member of our friendly team! Give us a call on 01943 871027, or you can email us: