Garage conversion
A garage conversion: the space you already own
The walls, roof and slab already stand, so a conversion is faster and cheaper than a new building. We level and insulate the floor, close the big door with a framed wall, and add a kitchen, a bath and a mini-split.
What we find under the old slab and inside the walls is the main unknown, which is why we ask for a site visit before we price one.
A studio or one bedroom, 350 to 450 sq ft
14 to 18 weeks to build
Priced after we check under the slab, in writing
What moves the price
What we check before we price a garage
A garage was built to hold a car, not a person. These are the places that surprise people.
The slab
Many garage floors slope toward the door and have no moisture barrier. Leveling and sealing come first.
Walls and roof
Garage walls are often bare studs. Insulation, drywall and sometimes new framing are needed.
Electric and gas
A sub-panel and new circuits are almost always needed. A gas line near the garage can limit where the kitchen goes.
Plumbing
The farther the bath is from the existing sewer line, the more cutting into the slab.
Fire separation
A wall shared with the house needs fire-rated drywall and a rated door.
Parking
State law generally does not make you replace the spaces. A few coastal and transit areas have their own rules.
The build weeks
What the weeks hold
A one-bedroom, 14 to 18 weeks.
- Weeks 1 to 3
Step 1: Demolition and floor
Clear the garage, cut for plumbing, level and seal the slab.
- Weeks 3 to 8
Step 2: Frame and rough-in
Close the garage door opening, run the circuits and pipes, set the window and the mini-split.
- Weeks 8 to 12
Step 3: Insulation and drywall
The city inspects the framing and the rough work, then the walls close.
- Weeks 12 to 18
Step 4: Finishes and final
Floor, cabinets, tile, fixtures, final inspection.
Rules to know
Parking, permits and what stays
A garage conversion generally does not trigger replacement parking under state law, and the unit can often be built without a new foundation. Your city may still ask for fire sprinklers if the house has them, or for upgrades to the panel or sewer connection.
If you want to keep one car space, ask about a conversion of half the garage.
If your house was built before 1978, ask us about lead paint before you sign. Work that disturbs painted surfaces needs specific lead-dust practices by a certified firm, and your quote says who holds the certification.
Questions
Asked about this type
Do I have to replace my garage parking?
State law generally does not require replacement parking when a garage becomes an ADU. We confirm that for your address, because a few areas near the coast and transit have their own rules.
What if you find a problem behind the wall or under the slab?
We stop, show you, and write up the fix and its cost. Nothing extra is done or billed until you sign that change in writing.
How long does it take?
Design takes about two months, the city review varies, and the build runs 10 to 36 weeks depending on the type. The weeks on the cards are build time only.
My house was built before 1978. Does that change anything?
It can. Homes built before 1978 may have lead paint. If work disturbs more than 6 square feet of painted surface inside or 20 outside, or touches windows or demolition, federal rules require specific lead-dust work practices by a certified firm. Tell us the year; we say before you sign whether the rule applies and who holds the certification.
Can we stay in the house during the build?
Yes for a detached unit, which is built in the yard. A junior ADU or garage conversion may mean a day or two without power or water; we tell you which days ahead of time.
Is your garage a candidate?
Text a photo and the address. We check the parcel and tell you what we would look at on site.