Nearly a third of Birmingham households have no car
At the 2021 Census, 31.7% of households in the city had no car or van, against 23.3% across England and Wales. Plenty of the garages that do exist never see a car.
The council's own design rules back up what most owners already suspect about a small garage. The Streets and Spaces manual in the Birmingham Design Guide (2022) asks for new garages of at least 6m by 3m inside, or 7m by 3.3m if bikes go in too, and says smaller garages will not be counted as a parking space. The Parking SPD, adopted in November 2021, says a garage only counts towards parking if it has adequate functional space.
What catches people is the drive. Once the garage becomes a room, the car has to sit in front of the house, and the city is wary of front gardens turned to tarmac. City Note LW-21 says replacing a front garden and its boundary with open hard standing for parking will be resisted, partly because it can make local flooding worse. A new dropped kerb needs approval from the council's Highways Department, and sometimes planning permission as well. If your drive already takes a car at 4.8m by 2.4m, the size of a standard bay in the guide, you're in a far better position.
Matching the conversion to the house
How each type tends to work here, with a link to a longer guide.
Home office. The obvious use for a short garage that never took a modern car. It is still a habitable room, so building control will want insulation, ventilation and a proper floor.
Integral garage. Don't expect one on a Victorian terrace in Moseley or Selly Park, built long before cars. The design guide wants garage doors that don't dominate the front, and the same eye falls on whatever replaces them.
Single garage. Measure inside first. Anything under 6m by 3m was never a parking space in the council's eyes, which helps if an application is ever needed.
Read our full guide: Single Garage Conversion: What Is Involved and What to Budget For →
Utility or playroom. A partial conversion keeps the front as storage and puts a utility or playroom behind. On the Calthorpe Estate that approach also helps with the rule that you keep the look of the garage doors.
Bedroom. A ground-floor bedroom brings fire escape into the building control discussion, which Approved Document B covers. Think twice in the parts of Perry Beeches or Selly Park North that flooded inside in 2016.
Double garage. Usually part of a larger detached house, and only about one Birmingham home in nine is detached. Convert one bay and keep the other, and nobody needs to argue about where the car goes.
Gym or studio. The slab will take the weights, but it still needs a new damp membrane. If it shares a wall with next door's garage, sort the sound out before the music starts.
Detached garage. Using it as a workshop or hobby room that stays part of the household typically needs no planning permission. Turning it into a separate home is a different matter, and the Planning Portal says permission may be needed whatever the building work.
The two approvals. Internal work that doesn't enlarge the house usually needs no planning application, unless a condition or an Article 4 direction says otherwise. Building regulations approval nearly always applies, through Acivico for the council or a private inspector.
Cost. We don't publish prices. The foundation under the old door opening, the floor build-up and any work to the drive are what move quotes apart, so ask each firm what they've allowed for.
Front elevations in St Agnes, Selly Park and Edgbaston
In most of the city, swapping an up-and-over door for brick and a window is a building regulations job, nothing more. A few places are tighter. The St Agnes direction in Moseley, confirmed in September 2009, removes the right to alter any part of a house that faces a highway, waterway or open space, and the right to lay a hard surface on that side. A road-facing garage door there needs permission to change. Selly Park's direction has the same schedule, covering houses on Selly Park Road, Pershore Road, Upland Road and nearby streets.
Moseley's own advice guide says any new parking area, front or side driveway included, needs planning permission, and that replacement doors and windows should match the originals exactly.
The Calthorpe Estate in Edgbaston adds its own layer. The residents' handbook allows a garage to become living space with consent under the scheme of management, provided you don't permanently lose the parking or storage. It also says the appearance of the garage doors must be retained. Ask the estate how it reads that before anything is drawn. Its consent doesn't replace planning permission.
What sits under the new floor
Most garage slabs were never laid as a room floor. The Planning Portal expects a new damp-proof membrane on the old concrete, insulation on top, and a screed of about 75mm, with the level often raised to meet the house. The in-fill wall may need its own foundation, which is where a lot of the digging goes.
Radon is a small worry here. In Public Health England's 2016 report for England, none of the 74 Birmingham homes measured reached the Action Level, even though testing leaned towards higher-risk spots. A postcode check on the UK radon map costs nothing, and so does a look on Planning Online for old conditions on your address.
Where these facts come from
- Birmingham City Council: Parking SPD (adopted November 2021)
- Birmingham Design Guide: Streets and Spaces City Manual (2022)
- Birmingham Design Guide: Healthy Living and Working City Manual (2022)
- Birmingham City Council: Census 2021 housing briefing
- Birmingham City Council: St Agnes Article 4 direction confirmation
- Birmingham City Council: Selly Park Article 4 direction
- Birmingham City Council: Moseley Article 4(2) advice guide
- Birmingham City Council: city-wide HMO Article 4 direction
- Birmingham City Council: flood investigation, June 2016
- Calthorpe Residents' Society: residents' handbook
- Public Health England: Radon in homes in England, 2016 data report
- Planning Portal: garage conversion planning permission
- Planning Portal: garage conversion flooring
- Planning Portal: building regulations for garage conversions
- Planning Portal: converting a garage into a workshop
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Questions people in Birmingham ask
My garage is too small for my car. Does Birmingham still treat it as a parking space?
Not under its current design guide. The Streets and Spaces manual says garages smaller than 6m by 3m inside will not be counted as a parking space. That matters mainly if an application is needed, when officers look at whether the drive still takes a car.
Can I pave the front garden to make up for the lost space?
Ask first. The council's design guide says replacing front gardens and boundaries with open hard standing will be resisted, and a new dropped kerb needs approval from Highways. In St Agnes, Selly Park and the Moseley Article 4 area a new hard surface or driveway at the front needs planning permission.
We're on the Calthorpe Estate. Can we brick up the garage door?
Not if it changes how the front looks. The handbook allows conversions with the scheme's consent but says the appearance of the garage doors must be kept, in a style that reflects the original house.
Can I use my converted garage as a music room on a semi in Selly Oak?
As a room used by the household, planning permission is typically not needed for the inside work, though building regulations still apply. Turning the house into a small HMO for three to six sharers is another matter. The city-wide Article 4 direction has required planning permission for that since June 2020.