We turn an attached or detached garage into a legal living unit. Framing, insulation, a kitchen and bath, new windows, and the electrical and plumbing to make it real.
Converting a garage is usually the cheapest way to add a legal unit, because the walls and roof are already there. We turn an attached or detached garage into a code-legal studio or one-bedroom apartment, with framing, insulation, a kitchen and bath, real windows in place of the old roll-up door, and the electrical and plumbing that makes it a home instead of a storage space.
A lot of Bellingham's garages were built with uninsulated walls, a slab poured with no vapor barrier, and a panel that can't carry a kitchen and a heat pump. That is the real work of a good conversion. We insulate and air-seal to current Washington energy code, deal with the slab moisture so the floor stays dry, and size the electrical so the unit runs without tripping. The total dollars are lower than a new cottage, but the cost per square foot is similar once you add everything a living unit needs.
What it actually costs.
Garage conversion $80,000 to $150,000
Attached vs. detachedA detached garage adds 20% to 30% for utility runs
Slab and wallsMoisture control and insulation on an old garage
ElectricalPanel and service upgrades for a kitchen and heat pump
Finish levelRental-grade vs. owner-quality finishes
Our four-step process.
Free feasibility check
We confirm the garage can legally become a unit on your lot, check the slab and the panel, and give you a realistic budget.
Design and permit
We draw the conversion, spec the insulation and egress, and pull the permit with the City or County.
Convert and build
We frame, insulate, run plumbing and electrical, set the kitchen and bath, and replace the garage door with a wall and windows.
Final inspection and walkthrough
We pass final inspection, walk it with you, and close out the punch list.
Why hire a real crew for this.
Usually the lowest total cost of any ADU path
Attached or detached garages both work
Insulated and air-sealed to current WA energy code
Slab moisture and panel upgrades handled, not skipped
Permit and inspections run by us, start to finish
Frequently asked questions.
How much does a garage conversion cost in Bellingham?
Most garage conversions in Bellingham run $80,000 to $150,000. An attached garage is on the lower end because the utilities are close. A detached garage usually adds 20% to 30% because we have to run water, sewer, and power out to it. The price covers framing, insulation, a kitchen and bath, new windows, and the electrical and plumbing to make it a legal unit. We hand you a line-item quote after a site visit.
Is converting my garage cheaper than building new?
Usually yes on total dollars, because a garage is smaller and the structure already exists. But the cost per square foot ends up similar to a new cottage once you add the kitchen, bath, insulation, egress, and utilities, since those cost the same whether the unit is new or converted. We give you both numbers so you can compare a conversion against a detached ADU for your lot.
Can a detached garage become a legal ADU in Bellingham?
Yes. A detached garage can be converted into a legal detached ADU as long as your lot allows it, which we confirm in the free feasibility check. The extra cost over an attached conversion comes from trenching water, sewer, and power out to the detached structure and bringing its slab and walls up to current energy code. We handle the permit through the City of Bellingham or Whatcom County.
Ready for a free garage conversion quote?
Tell us about your project and your lot. We'll reply within 15 minutes during business hours.