Planning guide
Do I need planning permission for an extension?
Often not. A great many rear extensions are built under permitted development, which is a national right rather than something you apply for. But the exceptions are wide, and in Kent, where conservation areas and listed stock are common, the exceptions catch a lot of houses. Here is how to work out which side of the line you are on.
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Work through these five questions
In this order. The first no you hit is usually your answer.
- Step 1
Is it a house, not a flat or maisonette?
Permitted development rights for extensions apply to houses. Flats and maisonettes need an application.
- Step 2
Have the rights been removed?
Many newer estates carry a planning condition removing permitted development, and Article 4 directions do the same in some conservation areas. Check your title and ask the council.
- Step 3
Is the house listed?
Listed building consent is a separate requirement and applies to work affecting the building's character, inside as well as out.
- Step 4
Where is the extension going?
Rear is the most permissive. Side is more restricted. Anything forward of the principal elevation almost always needs an application.
- Step 5
How big is it?
Depth, height and how much of the garden gets built on all have limits. Exceed one and it becomes a planning application rather than a refusal.
What tends to catch Kent homeowners out
Conservation areas. Tunbridge Wells, Faversham, Canterbury, Tenterden, Cranbrook, Sevenoaks town and many village centres all have designated areas where side extensions and roof alterations lose their permitted development rights and materials come under scrutiny. Being in one does not mean no, it means the design has to earn its approval.
The High Weald National Landscape. A large part of our patch sits inside it, and the tighter limits that apply in protected landscapes catch extensions that would be routine a few miles away.
Previous extensions. Permitted development allowances are cumulative across the life of the house, not per owner. A 1990s conservatory may have already used up what you were counting on.
None of that is a reason to abandon a project. It is a reason to establish the position before you pay for detailed drawings.
Good practice whichever route applies
- Ask the local planning authority for a pre application view on anything unusual
- Get a lawful development certificate if you build under permitted development, because it proves the position when you sell
- Treat building regulations as a separate approval that applies either way
- Talk to neighbours early, especially where a boundary or shared wall is involved
- Check the Planning Portal for the current national limits before relying on anything you read second hand
We handle applications as part of the build
Design, drawings, the application and the follow up with the case officer are all things we do in house, then we build what was approved. Free site visit first so you know the planning position before you spend anything.
FAQs
Common questions
How do I know if permitted development has been removed from my house?
Check the planning conditions on the original approval for your estate and ask the local planning authority whether an Article 4 direction covers your road. Both are quick enquiries.
Is a lawful development certificate worth getting?
Yes if you build under permitted development. It is your evidence that the work was lawful, and buyers' solicitors ask for it.
Does a conservation area mean I cannot extend?
No. It means the design, materials and position get closer attention, and some permitted development rights fall away. Well designed rear extensions are approved in conservation areas regularly.
Do I still need building regulations if I do not need planning?
Yes. They are entirely separate. Planning controls what a building looks like and where it sits, building regulations control how it is built.
Who applies, me or the builder?
We can submit on your behalf and deal with the case officer, which is usually faster because queries come to the people who drew it.
What if I build without permission by mistake?
Speak to the council early. Retrospective applications exist, but they are a far worse position than checking first, and enforcement is expensive.
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