01Short answer
Usually not for a house, with a few exceptions
Most roof windows on a house are covered by permitted development, which means the right to build without a planning application, as long as some simple limits are met.
Permitted development rights are national rules that let owners of houses make certain changes without applying to the council. Roof windows and rooflights fall under a part of those rules called Class C. For an ordinary house, that is the usual starting point, and it is why most people fitting a skylight into a roof slope never need to submit anything.
So do roof windows need planning permission? The word "usually" matters. The rules have conditions, they do not apply to every type of building, and your council can remove them for a particular street or area. So the straight answer is yes for some homes and no for others, and you can check which in a few minutes.
Our fuller guide to skylight planning permission goes through the same ground in more depth. This page gives the roof window version.
02The limits
The three conditions for a house
A roof window on a house stays within permitted development when it passes all three tests below.
- It projects no more than 150mm beyond the plane of the existing roof slope. A flush roof window sits well inside that.
- Its top edge stays below the roof's high point, and on a pitched roof that high point is the ridge.
- If it is in a side-facing slope, any part of it lower than 1.7m above the floor of the room is obscure-glazed and non-opening.
The third rule is about neighbours, and it catches people out. A roof window on a side slope that gives a view into next door's garden or windows is limited unless the low part is frosted and fixed shut. A window on the front or rear slope does not carry that condition.
03When it differs
Where permitted development does not apply
Some buildings and some places are outside the usual rule, and you need to know before you order.
Flats and maisonettes
Class C does not cover them. A roof window in a flat or maisonette usually needs permission from the council and may need the freeholder's agreement as well.
Listed buildings
If the house is listed, a new roof window needs listed building consent whatever its size, and the council decides where it goes and what it looks like.
Conservation areas sit in between. A conservation area does not by itself remove permitted development for a roof window. But the council can add an Article 4 direction, which takes some rights away in a defined area, and that can bring a skylight back under planning control. Whether your road has one is something to check with the council. Do not assume either way. We cover the south Essex picture in conservation areas and listed homes in south Essex.
Past work can matter too. Some homes have had permitted development rights taken away by a condition on an earlier planning permission, which is common on newer estates. Your deeds or the planning history will show it.
04Checking
How to find out for your own home
Four short steps give you a clear answer without paying anyone.
- Work out whether you have a house, or a flat or maisonette. If it is a flat, plan on asking the council.
- Check whether the building is listed. If it is, you need listed building consent.
- Ask your council whether your road is in a conservation area or under an Article 4 direction.
- Measure how far the window will stand proud of the roof, and which slope it faces.
The government's Planning Portal has a guide to roof work under permitted development, and your local planning authority can confirm anything specific to your property. If you want certainty in writing, you can apply to the council for a lawful development certificate, which confirms the work is permitted.
05Building Regs
Planning is one thing, Building Regulations another
Even when no planning permission is needed, a roof window is still building work with its own rules.
Building Regulations cover things like heat loss, the structure around the opening and the safety of the glazing. Swapping a complete roof window, frame and glass together, must be notified because it is a controlled fitting under Part L, the part dealing with energy efficiency. Changing just the sealed unit does not need that. Cutting a new opening into a roof can also involve the rafters, and so the structure.
Our fitting meets the Building Regulations in force today, and we deal with the Building Control notification whenever the job calls for one. That is part of how we keep rooms bright and warm, since the same rules set the glazing and insulation standard around the opening. Browse the range under roof windows, or see how they come into a conversion in roof windows for loft conversions.
If you are unsure what applies to your home, book a free survey through our quote page and ask us while we are there.
Worried a roof window needs a planning application?
Do I need permission for a roof window in a loft conversion?
Adding roof windows alone usually falls under permitted development on a house, within the limits above. A dormer is a different matter and has its own rules, so check with the council if you are adding one.
Does being in a conservation area mean I need planning permission?
Not by itself. But an Article 4 direction can change that, so check with the council before you order.
Can I fit a roof window in a flat?
Class C does not cover flats or maisonettes, so you would normally need to ask the council, and possibly the freeholder, first.
Who does the Building Control notification?
We do, where the work is notifiable. You do not need to arrange it yourself.
