Useful ranges, not a remote quotation.
For early planning, many straightforward single-garage conversions sit around £13,000 to £20,000. A bedroom with an en-suite, extensive structural changes or a double garage can cost materially more.
These are indicative planning figures rather than offers or quotations. The condition of the building and the design can only be assessed properly at the property.
What changes the price?
Garage type and existing construction
An integral garage may already share walls, services and access with the house. A detached garage can require more work to create a comfortable, compliant room and connect it to the main property.
The garage door opening
Replacing the door with an insulated wall and window is common. The opening, foundations and chosen external finish all influence the work involved.
Floor level, damp and insulation
Garages were not usually designed as living rooms. Bringing the floor up, controlling moisture and meeting the relevant thermal standards can be a meaningful part of the build.
Plumbing and drainage
A study or playroom is generally simpler than an en-suite bedroom or utility room. The distance to suitable water and drainage connections matters.
Professional and approval costs
Allow for drawings, any structural input, the building warrant fee and other professional work required for the particular design. Check whether these are included in each quotation.
Compare the scope, not just the total.
Two quotations can describe quite different finished rooms. A useful written quotation should make clear what is included and excluded, including:
- design, drawings and building-warrant responsibilities;
- structural work and treatment of the former garage opening;
- insulation, heating, ventilation and electrical work;
- windows, doors, plastering, joinery, flooring and decoration;
- bathroom fittings and drainage, where relevant;
- waste removal, VAT, payment stages and anticipated programme.
Build a sensible contingency into the plan.
Older buildings and concealed areas can reveal extra work once construction begins. Keep part of the available budget outside the base quotation and agree how variations will be priced and approved before work starts.
If you are still deciding what the room should become, settle that first: room use drives the requirements for drainage, daylight, ventilation, heating, storage and finishes.