DATA-BACKED GUIDE · UPDATED JULY 2026
How to get honest quotes for a garage conversion
The gap between two garage conversion quotes can be huge, and it is not always because one builder is greedy. Often they have simply priced different jobs. Here is how to get quotes you can actually compare, then check them against the real prices below.
The quick version
- Ask every builder to price the same scope so you compare like with like.
- A garage conversion is building work, so 20% VAT should be shown clearly, not bolted on later.
- Local builders usually come in below national conversion firms for the same job.
- Get three quotes so you can spot the outlier that is either cutting corners or padding the price.
What people actually paid
Real prices, in people's own words
- £3,000“Ours was about £3k. We had to pay separately to have a new roof”
- £6,000“We have just had one done and it cost 6k.”
- £9,000“Mine was 9K. Internal garage, large for a single garage.”
- £10,000“Ours was around the 10k Mark”
- £10,000“We paid around £10,000 for the project. That included flooring too.”
- £15,000“We've just spent 15k on a double garage conversion in south wales”
Genuine amounts posted publicly. We publish the price and the quote, never the person.
Why the price varies so much
Quotes vary because builders make different assumptions about what your garage needs. One might allow for a full new floor and damp-proof membrane, another might assume the slab is fine. One might include finishing the room ready to decorate, another might stop at bare plaster. The door opening, the insulation spec and whether any plumbing is involved all move the number. Until every quote covers the same list of work, the cheapest one on paper can end up the dearest once the extras land.
How to pay less
- Write a short scope of what you want and hand the same one to each builder so the quotes line up.
- Get three quotes and lean towards established local trades rather than a national brand that sells finance.
- Ask what is excluded, since flooring, decorating and electrics are common gaps that reappear as extras.
- Pay the deposit by credit card for Section 75 cover, and never hand over a big cash sum up front.
Common questions
How many quotes should I get for a garage conversion?
Three is the sweet spot. One quote gives you nothing to judge it against, and two can both be off. Three lets you see the middle ground and question anything that sits well above or below it.
Should I use a national garage conversion company?
You can, but national firms usually quote above local builders for the same work, partly to cover advertising and finance deals. If you go that route, still get three quotes from local trades so you know what a fair price looks like.
What should a written garage conversion quote include?
It should list the floor works, insulation, how the door opening is filled, electrics, plastering and any decorating, plus VAT. A vague one-line price is a red flag. The more detail it holds, the easier it is to keep the builder to it.