Do You Need Planning Permission for a Dormer Loft Conversion?

The basic rule of thumb for any loft conversion is permission is not required if you do not extend or alter the roof space to exceed the limits and conditions set out by the government. Invariably, a Dormer loft conversion does not need planning permission. It is classed as a “permitted development”. Full details of legislation can be found here.

A Popular Choice

Paul Foley from Touchstone loft conversions says the Dormer is the most popular style of loft extension because it maximises the available space. A Dormer loft conversion creates more floor space and headroom by extending vertically from an existing sloping roof. It is literally a wall that projects vertically from the original roof making and in doing so making it square. Because of this construction, inside the property the room has a horizontal roof and vertical walls “as usual”.


One of the drawbacks of a dormer is it can look a bit “squared off” and some people find this a little unattractive. However, with a little creativity and a good designer it can be made to look very attractive. One of the specifics of planning permission legislation, is that the materials used must be in keeping with the existing property. This can be a tad limiting to creativity, but a hipped roof of gabled front can work wonders with regards to the visual design. The drawback with this is you do lose space inside and it does cost extra money to achieve due to the complexity of the work.

Different Types of Dormer

A Dormer loft extension can usually be constructed within the specs for “permitted development”. However, if you do start to get fancy with it planning permission might be needed. It depends on the style you choose. An I-shaped dormer is usually considered to be the best option for a mid-terrace house. The hipped roof and gabled dormer as mentioned previously are among the most expensive. The flat roof and shed dormer are usually the least expensive designs.


Houses in designated areas of outstanding natural beauty, conservation areas, world heritage sites, national parks and the broads cannot have loft extensions. Flats and maisonettes also fall into a different list of specifics with regards to permissions. Some other properties, like barn conversions or change of use building might also need planning permission or be excluded. “Permitted Development” is applicable to houses only.

The Alternatives

There are different styles of loft conversion and some building companies specialise in this work. They will be able to advise you if your ideas need planning permission or not relatively quickly. It is a good idea to list what you want and even provide a few drawings to visualise your ideas. Budget is also a major consideration. A professional will be able to realise your ideas while respecting your budget. Planning permission adds to costs, which means a Dormer Loft Conversion can provide a more economical solution. Without doubt, something to consider when making your choices.