Guides · Garage conversion guides
What goes into a garage conversion: damp-proofing, insulation, heating and electrics.
In short: A garage needs four things before it is a comfortable room: damp-proofing, because garage floors often sit below the house's damp-proof course; insulation to house standard; heating, usually extended from the main system; and electrics planned around how the room will be used. Getting these right is what separates a conversion from a garage with carpet.
Do garage conversions need damp-proofing?
This is one of the most common issues we find during a garage conversion survey, and it needs addressing properly before any finishing work starts.
Why it's an issue
Garage floors often sit below the damp-proof course of the main house, since garages weren't originally built as habitable space. Left unaddressed, this can lead to persistent damp in the converted room.
How it's fixed
Damp-proofing typically involves raising the floor level, installing a proper damp-proof membrane, and addressing any damp-proof course issues in the walls. This is assessed during the survey and priced into the conversion from the outset.
How is a garage conversion insulated?
Garages are rarely built to the same insulation standard as the rest of the house, so bringing this up to scratch is a standard part of most conversions.
Floor and walls
The existing floor is usually raised and insulated as part of the conversion, since garage floors are typically lower than the house floor level and poorly insulated. Wall insulation is added to bring the room in line with the rest of the house's thermal performance.
Roof and door opening
Roof insulation is checked and upgraded where needed, and the former garage door opening — whether bricked up or replaced with a window — is insulated and detailed to avoid becoming a cold spot or source of draughts.
How is a garage conversion heated?
Heating is usually extended from the main house's existing system, which is more straightforward for an integral garage than a detached one.
Extending the existing system
For an integral garage, extending the central heating system with a new radiator or underfloor heating loop is usually the most practical option, since the pipework doesn't have far to travel.
Detached garages
A detached garage conversion may need its own heating solution, such as electric heating, if extending pipework from the house isn't practical, similar to the approach used for garden rooms.
What electrics does a garage conversion need?
Electrics are planned around the room's intended use, whether that's a bedroom, office, gym or playroom.
Sockets and lighting
First and second fix electrics are extended from the main house, with sockets, lighting and data points positioned around the room's planned layout and use.
Consumer unit capacity
We check whether your existing consumer unit has capacity for the extra circuits a conversion needs, particularly if the room includes heating, an en-suite, or equipment such as a home gym setup.
Frequently asked questions
What goes into a garage conversion: damp-proofing, insulation, heating and electrics: FAQs.
How do I know if my garage has a damp problem before converting it?
We check for this as part of the survey, looking at floor level relative to the damp-proof course and any visible signs of damp in the walls.
Is garage insulation different from house insulation?
The principles are the same, but garages often need more remedial work first, since they weren't originally built to the same standard as the main house.
Is underfloor heating a good option for a garage conversion?
It can be, particularly since floor insulation and levelling are usually being done anyway as part of the conversion, making it a practical time to add it.
Does garage conversion electrical work need to be certified?
Yes, all electrical work must meet Part P requirements and be certified by a competent, registered electrician.
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