Planning permission for outbuildings & garden rooms
Garden rooms, offices, studios and sheds are usually permitted development as buildings incidental to the home: within limits on coverage, height and position.
A garden office or studio is a popular way to gain space without extending the house. As long as the building is incidental to enjoying your home, not a separate dwelling, it usually falls under permitted development.
- Single-storey, no more than 2.5m high within 2m of any boundary
- Otherwise up to 3m (or 4m with a dual-pitched roof) to the ridge, 2.5m eaves
- Outbuildings and extensions together covering no more than half the land around the original house
- Positioned to the side or rear, not forward of the principal elevation, and for a purpose incidental to the home
- Living or sleeping accommodation, or use as a separate dwelling
- Buildings to the side of a house on designated land, and anything over 10m² within the curtilage of a listed building
- Homes in conservation areas, National Parks and AONBs (tighter limits)
- Verandas, balconies or raised platforms, and properties with rights removed
Don't forget building regs
Small detached outbuildings under 15m², or under 30m² and far enough from a boundary, can be exempt from building regulations, but a garden room you work or sleep in, or one with plumbing, usually needs to comply. We advise on the threshold your design crosses.
We design garden rooms that stay within permitted development where possible, and keep the “incidental use” test in mind so the building does not accidentally need permission. Where it is a working office you need warm and usable year-round, we detail it to building-regs standard. Talk it through on the contact page.
Frequently asked
Do I need planning permission for a garden office?
Usually not, if it is single-storey, within the height limits, covers no more than half the garden with any other outbuildings, and is used as space incidental to the home, not as separate living accommodation. Designated land and listed buildings are the main exceptions.
Can I live or sleep in a garden room under permitted development?
No. Permitted development for outbuildings is for uses incidental to the house, such as an office, gym or studio. Using it as self-contained living or sleeping accommodation is a separate use that needs planning permission.
Not sure where your project stands?
Checking whether you need planning permission is one of the first things we do: on the house, before any drawings. Tell us about your project and we'll confirm the route.