The space is already there.
An office, a studio, or an apartment with its own door. The cheapest of the three — when it works.
Living space, or an apartment.
A bonus room, office or studio
Part of the house. Follows the house's rules.
Own door, own kitchen
An attached ADU. Your city's ADU rules apply — friendlier since 2023.
Three things.
The slab and the ceiling
A garage floor sits low. A finished floor and a legal ceiling have to fit.
Where the plumbing can run
A bath needs a drain with fall to the sewer — a trench or a pump.
Your HOA
Conversions are what covenants most often ban. Check yours first.
Parking: some cities require a replacement space. For an apartment, state law bars any requirement within half a mile of major transit, and caps it at one space on lots under 6,000 sq ft. What HB 1337 changed →
The cheapest of the three — sometimes still not worth it.
The report does the arithmetic for your garage, with a sourced planning range. A fixed price comes only after a site visit. Construction by United Signature, WA reg. UNITESE790Q3.
A new slab, a pumped drain, a full energy envelope.
A level slab, plumbing nearby, headroom already there.
The report says so when the math doesn't work.
Three quick questions
Do I lose my parking?
You lose the garage. Whether a replacement space is required depends on your city.
Can I rent it out?
With its own door and kitchen, in most cities, yes. Short-term rental rules are separate.
Does it add value?
Permitted space usually appraises; unpermitted usually doesn't. The report is not an appraisal.