Acton ADU
San Francisco Bay AreaSan Francisco Bay Area ADU builder that says it has more than 30 years of experience.
Order is editorial. Descriptions come from each company's own website, last checked October 2026. A listing is not an endorsement. How we work.
SnapADU
San DiegoDesigns, permits and builds ADUs in San Diego.
Better Place Design & Build
San DiegoDetached ADU design-build team in San Diego that handles feasibility, design, permits and construction, with the price fixed before you sign.
Backyard Estates
Inland EmpireDesigns and builds custom ADUs across the Inland Empire and Los Angeles, with one team for design, permits and construction.
prefabADU
CaliforniaCalifornia general contractor building custom homes and ADUs since 2004.
Backyard Unlimited
SacramentoCustom shed and ADU builder in Sacramento.
Housable
CaliforniaFinds the extra units that could fit on rental property you already own in California, then handles feasibility, permits and construction.
ConnectADU
San JosePlans backyard ADUs in San Jose for families who want aging parents close by, starting with a planning call.
microhouse
Design collaborative focused on detached ADUs and small houses.
Backyard ADUs
Maine and MassachusettsBuilds small houses and ADUs in backyards or on raw land in Maine and Massachusetts.
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Costs
What an ADU really costs, and where the money goes
The best public numbers we could find, what they include, and why a small unit costs more per square foot than your house did.
4 min read · 3 sources
Costs
Five real ADU projects, broken down line by line
A public housing agency built five ADUs and published every cost. Here is what they paid for permits, surveys, design and construction.
3 min read · 2 sources
Design and build
Prefab vs site-built ADUs
Factory-built units can be faster and sometimes cheaper. The savings depend on your lot, your city and what the quote leaves out.
3 min read · 4 sourcesNewsletter
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