Completed detached ADU by A1 Building Contractors in the Sacramento region

Sacramento ADU Builder — Granite Bay & Roseville

Veteran-Owned Sacramento ADU Builders · Detached ADUs, Garage Conversions & Additions

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ADU, garage conversion and custom home builder in the Sacramento region

A1 Building Contractors LLC is a veteran-owned, CSLB-licensed general contractor based in Roseville, California. We design, permit and build detached ADUs, attached ADUs, junior ADUs, garage conversions, home additions and custom homes across Sacramento, Placer, El Dorado, Yolo and Sutter counties.

Homeowners come to us for one of three reasons: rental income from a backyard unit, housing a parent or adult child close by, or replacing an aging home with a custom build on the same lot. Whichever it is, the work runs through one contract — feasibility, design, engineering, Title 24, plan check and construction — so there is a single accountable team from the first site walk to the final inspection.

Pricing is quoted line by line in 2026 Sacramento-region numbers. Most detached ADUs land between $135,000 and $255,000 all-in including design, permits, utility connections, construction and standard finishes. Garage conversions come in well below that because the slab, walls and roof already exist. California waives most impact fees on ADUs under 750 square feet.

Cities we build in

We build across the greater Sacramento region, with dedicated cost, permit and plan guidance for each jurisdiction we work in.

Common questions about ADU and custom home construction in Sacramento

The three questions homeowners ask most, answered plainly. Pricing reflects 2026 Sacramento-region construction costs including permits, utility connections and standard finishes.

How we deliver ADU and custom home projects

Every project runs through the same five-stage process, so you know what happens next and what it costs before construction starts. We handle design, engineering, jurisdictional plan check and construction under one contract, which keeps the schedule and the budget with a single accountable team.

Why homeowners choose A1 for Sacramento-region construction

A1 Building Contractors LLC is a veteran-owned, CSLB-licensed general contractor based in Roseville, CA. We design, permit and build ADUs, garage conversions, home additions and custom homes across the Sacramento region, with transparent line-item pricing and a single point of contact from first site walk to final inspection.