The short answer
For a house, usually not. A rooflight in a flat roof is normally permitted development if it stands no more than 150 mm proud of the original roof, frame included, and no higher than the highest part of that roof. A kerb that lifts the unit past 150 mm brings the job back to the council. A flat or maisonette is outside the householder rights altogether. We check your roof and your house at survey.
- Free survey, fixed written quote
- 10-year workmanship guarantee
Where the 150 mm is measured from
The limit runs from the plane of the original roof. On a flat roof that plane is the roof surface as it stood when built, so the height of the kerb and the glass above it is what the planning rules add up. A low kerb with a slim frame can sit inside the limit. A tall kerb, which a thickly insulated roof may call for, can push the unit past it. A roof lantern normally stands more than 150 mm proud and so needs planning permission unless the council confirms otherwise; the full picture is in our guide to lantern planning and building regulations.
The word original deserves care. If the roof has been built up since the house was first put up, with extra insulation boards or a raised deck, the measurement still refers back to the roof as it was. We ask what the roof looked like before, and for the paperwork on any extension that carries the flat roof. The height of the kerb itself comes from the build-up, which is described on our upstands and kerbs page.
Frame depth counts as well as kerb height. A slim frame on a low upstand adds less than a deep kerb with a bulky cap. We write the combined height in millimetres on the survey sheet, so you can set it against the limit yourself or hand it to the council.
| Property | Planning position |
|---|---|
| House with its householder rights intact | Usually permitted development, if the height limits are met |
| Flat or maisonette | No householder rights, so an application is usually needed |
| House made by converting an office, shop or barn under permitted development | No householder rights under that change-of-use route |
| Listed house | Listed building consent for new or altered openings |
Flats, conversions and rights taken away
Householder permitted development belongs to houses. A flat on the first floor above a shop, or a maisonette with its own flat roof, falls outside it, so a rooflight there needs an application whatever its height. Lease terms and the freeholder's consent can matter too, which is a conversation for you and your managing agent.
Some houses have lost their rights even though they are houses. Householder rights also do not apply to a house that began as an office, shop, barn or comparable building and was turned into a home under the change-of-use permitted development rules, and a condition on a planning permission can remove them for a particular home. Check your decision notice for any wording that takes away permitted development, or ask the council, and we will read it with you at survey.
Conservation areas and listed houses
Living in a conservation area does not by itself remove the permitted development right for a rooflight. An Article 4 direction does, so the question to put to the council is whether one covers your street. Our answer on Article 4 and rooflights explains what to ask for.
A listed house is different. Its permitted development rights still exist on paper, but a new or altered opening in the roof will almost always need listed building consent. Read rooflights on listed buildings before drawing anything.
Asking the council to confirm
If the height is close to the line, the council can issue a lawful development certificate, which records in writing that the work is lawful. Applications go through the Planning Portal, where the form asks for the site, the proposed work and drawings showing the size and height of the unit. Where an application is needed instead, a householder application is the route, and we supply the dimensions of the unit and kerb that it asks for. Leave the fitting date open until a certificate or decision has come back, since any work that needs one should wait for it.
Building Regulations are a separate step and apply however planning goes: a new roof opening is building work, and we handle the Building Control notification where the work is notifiable. The wider rules are on our skylight planning permission page, and for the flat-roof basics see whether a flat roof can take a skylight. To have a roof read, book a free survey.
