2 November 2023 · Sharon Winson
Do you need planning permission to convert a double garage?
Usually not, if the structure and exterior stay as they are — but building regulations still apply, and some homes are exceptions.
You usually don't need planning permission to convert a double garage if the work is internal and the building's structure and exterior stay as they are. You will, though, almost certainly need to satisfy building regulations, and homes that are listed, in conservation areas or with restricted permitted development rights need consent — so check with your local authority first.
When is planning permission required for a double garage conversion?
Planning permission comes into play when the project goes beyond a straightforward internal fit-out. Expect to need it if the work involves:
• Structural changes — removing walls, altering the roofline or raising the roof beyond permitted development limits. • A change of use, such as turning the garage into self-contained living space. • A listed building, or a home in a conservation area. • A property whose permitted development rights have been removed by planning conditions — common on some newer estates.
If none of those apply, many double garage conversions proceed under permitted development without an application.
What does permitted development allow?
To stay within permitted development, a conversion generally must not enlarge the building beyond what the regulations set out, and must not significantly affect the amenity of the surrounding area. The rules are also more comfortable with modest, occasional-use spaces — a hobby room or summer-house-style space — than with anything approaching a self-contained dwelling: extensive plumbing such as a shower block, or sleeping accommodation, pushes the project towards needing permission.
These boundaries genuinely vary case by case, so treat this as a guide and confirm the specifics with your local planning authority before you commit.
Do building regulations apply even without planning permission?
Yes — and this is the part people most often miss. Building regulations are separate from planning permission and apply to garage conversions even when no planning application is needed. That means submitting either a building notice or a full plans application to your local council, and inspections during and after the work to sign it off.
It's protection, not red tape: the regulations are what guarantee the converted room is insulated, ventilated and safe to live in.
How do you apply if permission is needed?
Apply through your local planning authority — most councils take applications online, and their planning officers will tell you what drawings and details they need for a garage conversion. For borderline cases, a pre-application enquiry is a cheap way to find out where you stand before paying for a full application.
And once the double garage becomes a room, the cars and clutter still need somewhere to go — that's where a new garage in the garden earns its keep.
The Planning Portal's guidance on building regulations approval for outbuildings is the official reference. Related reading: do you need permission to turn a garage into a room? — and if you're replacing the space you're converting, see our double garages and prices.
Can I convert my double garage without telling the council?
Even when planning permission isn't needed, building regulations still apply — so the council needs a building notice or full plans application, plus inspections. Skipping that can cause real problems when you sell the house.
Does converting a double garage need planning permission if I keep the doors?
Keeping the exterior unchanged helps a conversion stay within permitted development, but it isn't the whole test — structural changes, change of use and property-specific conditions all matter. Check with your local planning authority.
Can a converted double garage include a bedroom?
Sleeping accommodation moves the project into stricter territory — building regulation approval is required, and planning permission may be too. Get advice from your local authority before designing around a bedroom.
What replaces the storage a double garage conversion removes?
Most owners add a new garage or shed in the garden. A Nucrete double garage is installed in around a day, with VAT, delivery and installation included in the price.