What Kent's highway authority counts as a parking space
Kent County Council is the highway authority for Canterbury, and in January 2025 it adopted new parking standards for development across the county. They are frank about garages. In suburban and rural locations the county won't count them as formal parking spaces at all.
The same standards recommend an internal size of 7.0 metres by 3.6 metres for a single garage, and 7.0 by 6.0 for a double. Get the tape measure out. A garage that falls short of today's standard was never much of a car space, which is a fair point if the planners ask what you're losing.
What usually matters more is the drive. Kent's standard for an outdoor car space is 5.0 by 2.5 metres. If your drive takes one or two cars at that size, you keep your parking when the garage becomes a room.
None of this decides whether you need permission. The Planning Portal says internal work that doesn't enlarge the house usually needs none, but some homes, often on newer estates, have had the right to convert taken away. Ask the council for the original decision notice for your house and read the conditions before you spend anything.
Old frontages, new windows and the Article 4 streets
Swapping a garage door for a window and a section of wall changes the front of the house, and in parts of Canterbury that is exactly what the planners control. The council's 2007 heritage guidance explains that its Article 4 directions require permission for minor alterations to frontages, doors and windows among them. Around 1,200 unlisted buildings in the city conservation area fall under the 1985 direction.
The same guidance gives a clue about what will pass. For suburban houses built after 1920, uPVC windows may be approved if the style is right. On older houses it wants traditional sashes matched. So on an Edwardian villa, plan on timber and a window that copies the ones above it.
Mind the front garden too. The guidance names hardstanding for parking as a threat to gardens in conservation areas, so paving the lawn to replace the garage may meet resistance.
Ten ways to use the space in a Canterbury house
Detached and semi-detached houses each make up close to a third of the district's homes, so garages are common. Each option below links to a full guide.
Integral garage. In Tyler Hill, the parish design statement records that every house in Sunnymead, the 21 detached homes built there between 1980 and 1983, came with an integral double garage. Read the decision notice first.
Double garage. Converting one bay and leaving the other for a car is the neat answer on a house like that.
Single garage. The infill wall where the door was usually needs its own footing, and the new floor has to lap into the damp course of the existing walls. In the historic centre, that footing counts as ground works for the archaeology rule.
Read our full guide: Single Garage Conversion: What Is Involved and What to Budget For →
Home office. A sensible choice for anyone splitting the week between home and a fast train out of Canterbury West. It still needs insulating to the standard of a habitable room.
Bedroom. A ground-floor room needs a safe way out in a fire, which normally means an escape window or a door to a hall that leads outside. Near the Stour in Westgate or Wincheap, look at the flood map before anyone sleeps downstairs.
Utility or playroom. Keeping the front half as a store with the original door, and fitting out the back, avoids changing the frontage at all. On an Article 4 street that can save an application.
Detached garage. Used by the household as a workshop or gym, a detached garage stays part of the house, and the Planning Portal says a hobby workshop typically needs no permission. Turning it into a separate home is another matter: planning permission may be needed whatever the works, and around the city the Stodmarsh water rules apply to new homes.
Gym or studio. For music, a garage wall shared with the neighbour's garage on a pair of semis needs proper sound insulation.
Planning and building control. Planning turns on your house's history, and on whether it is listed or under an Article 4 direction. Building control sign-off is needed almost every time a garage becomes a lived-in room, wherever you are.
Cost and value. We don't publish prices. A timber window in a conservation area or an archaeologist on site can push the figure up. Quotes from builders who have seen the garage will tell you more.
Before the builder starts
Building control for Canterbury is run through STG, the partnership the city shares with Medway, Swale and Gravesham, unless your builder appoints a private inspector. For a garage that needs a new footing and a rebuilt floor, full plans gives you approved drawings before work begins.
Ask about radon. A new habitable room may need radon protection where the potential is raised, so look up your address on the UKradon map before the slab is finished.
One local rule catches garage jobs in the old city. Inside the Area of Archaeological Importance, the council asks to hear about any digging well in advance, and a footing for the infill wall is digging. Tell them at the design stage, not the week the skip arrives.
Where these facts come from
- Kent County Council Parking Standards, 2025
- Heritage, Archaeology and Conservation guidance, 2007 (Canterbury City Council)
- Hackington Parish Design Statement (Hackington Parish Council)
- Make a building control application (Canterbury City Council)
- Areas of archaeological importance (Canterbury City Council)
- Garage conversion: planning permission (Planning Portal)
- Garage conversion tips (LABC)
- Converting a garage into a workshop (Planning Portal)
- Stodmarsh water quality (Canterbury City Council)
- Radon and building work (LABC)
- Flood risk assessment standing advice (GOV.UK)
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Questions people in Canterbury ask
Kent says garages aren't parking spaces. Does that mean Canterbury can't object when I convert mine?
Not on its own. The county's 2025 standards are about planning new homes, and they don't deal with conversions. What decides your case is whether a condition on your house removes the right to convert. If it doesn't, internal work normally needs no application.
Our house is in the city conservation area. Can we put a window where the garage door is?
Probably, with permission. The council's Article 4 directions control alterations to frontages, including doors and windows. A design that copies the house's existing windows, in timber on an older house, has the best chance.
We live in Sunnymead in Tyler Hill. Can we convert half of our double garage?
Usually that's the easiest route. Check the decision notice for your house first, because a condition from the original approval would still apply.
Do I need to tell the archaeologists about a garage conversion in the centre?
Only if there's digging. A new footing under the infill wall or a fresh drain run counts. Purely internal work, such as lining walls and laying a floor on the existing slab, doesn't.