Policy H17 and its four exceptions
Slough has something many towns don't: a planning policy written about garages in particular. Policy H17 of the 2004 Local Plan is still one of the saved policies the council uses to decide applications. It says converting an integral garage into a room, or into any other use, will be refused unless at least one of four things can be shown.
Parking can still be provided to the council's standard. The room is needed for a family member with special medical needs. The garage can't physically be used to park a car in the normal way. Or the house is in the town centre and the household won't need a car.
Most owners never meet the policy at all. The plan's own supporting text accepts that turning a garage into a habitable room is generally permitted development. H17 bites on the estates that were laid out on the assumption that cars would sit in garages, where the permission carries a condition stopping the garage being used for anything else. Lifting it takes a planning application, and the council says it will oppose losing the garage because of what overspill parking does to the street.
So the first job is finding out whether your estate has that condition. The planning team can check the house's planning history, and your conveyancing pack may already hold the permission.
Measure it against the council's own garage
Slough's Residential Extensions Guidelines, adopted in January 2010, set out what the council regards as a working garage, at least 2.5 metres wide and 5 metres deep inside. A drive in front should be 6 metres deep, or 5 if the garage has a suitably designed roller shutter.
Those numbers help with exception (c). If a car can't be driven in and the doors opened, you have the start of a case. Bring photos and the measurements to the planners rather than an argument.
How each type suits Slough houses
Integral. This is the type H17 names. If the estate permission carries a garage condition, you need an application and must meet one of the four exceptions. If it doesn't, the work is normally permitted development.
Single. Take the inside measurements first. A single garage well under 2.5 metres by 5 is storage in Slough's eyes as much as yours, which makes the planning side simpler where a condition applies.
Read our full guide: Single Garage Conversion: What Is Involved and What to Budget For →
Bedroom. Slough's households are bigger than England's average, so this is the usual request. Count the spaces left on the drive before you start, because that is the first thing the council asks where a condition applies.
Utility or playroom. The better choice in a house near Chalvey Ditch, Salt Hill Stream or Datchet Common Brook. Water damages a washing machine. It does far worse to a bedroom someone is asleep in.
Home office. A room off the hall works well in a busy house. Building control still treats it as habitable, so it needs the same insulation and background ventilation as a bedroom.
Double. Rare at the side of a Slough house, because the guide normally refuses side doubles as unbalancing. If yours is at the back, a car space left inside it may be all you need to meet exception (a).
Gym or studio. On a semi or terrace the party wall carries noise, so line it before the rubber floor goes down. A music studio needs more than a gym.
Detached. Used by the household as a workshop or office, it stays part of the house. Slough's 2004 plan wants any granny annexe built as part of the home, never a separate dwelling.
Planning and sign-off. Planning turns on that estate condition and H17. Building control is a different question, and turning a garage into living space normally needs approval under the building regulations wherever you live.
Cost. We don't print Slough prices. What moves a quote here is whether you need an application first, the footing under the old door and how far the floor has to rise.
Drives, floors and the brooks
Converting often means more cars on the front. Slough's guide wants front gardens to follow the pattern of the street, normally allows only a single-width dropped kerb, and says new hard surfacing over 5 square metres may need permission unless it is porous or drains to a porous area.
Inside, the Planning Portal says the old slab can stay as a base, but it needs a new membrane and insulation, and you may want to lift it to the level of the house. The wall built into the old door opening may need its own foundation. A room reached only through another room needs an escape window, and LABC gives the opening size.
Then check two maps. The Environment Agency's flood map will show whether the house sits near one of the brooks that run through Slough. The UKradon map shows the chance of raised radon at your address, and your builder should see the result before the floor is designed.
Sign-off comes from Slough Building Control at Observatory House on Windsor Road, unless your builder uses an approved inspector. File the completion certificate with your deeds.
Where these facts come from
- Slough Borough Council: Local Plan 2004 saved policies (H17)
- Slough Borough Council: consistency with the NPPF (saved policies in use)
- Slough Borough Council: Residential Extensions Guidelines SPD 2010
- Slough Borough Council: Equalities in Housing 2023 (Census 2021)
- Slough Borough Council: building control and your home
- Environment Agency: Slough flood alleviation scheme
- Planning Portal: garage conversion planning permission
- Planning Portal: garage conversion building regulations
- Planning Portal: in-fill garage door
- Planning Portal: garage conversion flooring
- LABC: garage conversion tips from building control
- UKradon: radon maps
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Questions people in Slough ask
Our estate permission bans converting the garage. Is there any way round it in Slough?
You can apply to have the condition lifted. The council will judge it against Policy H17 and expect you to show at least one of its four exceptions, such as enough parking left on the drive or a garage too small to park in.
My father needs a downstairs room. Does that count for anything?
Yes. H17 lists accommodating a family member with special medical needs as one of its exceptions. Send medical evidence with the application, and design the room so building control can approve it as a bedroom.
We live near the town centre and don't own a car. Can we convert?
Exception (d) covers homes in the town centre where the household can show it won't need a car. If your house has a garage condition, explain that in the application with your evidence.
Can I keep the front half as a store with a roller shutter?
Slough's guide accepts roller shutters only if the design suits the house, and it uses them to allow a 5 metre drive instead of 6. Show the door on your drawings so the planners can judge it.