A Junior ADU is a separate living unit (max 500 sq ft) created inside the walls of your existing single-family home. JADUs share the main home's footprint, so there's no new foundation, no new roof, and no impact fees — making them the lowest-cost legal rental unit you can build in Sacramento County. The trade-off: California law requires the owner to live in either the main house or the JADU (one-time owner-occupancy). We build JADUs across Sacramento, Granite Bay, Roseville, Folsom, and Elk Grove using attached garage conversions, basement build-outs, and master-suite splits.
Size: 150–500 sq ft
Bedrooms: 0–1 · Baths: 1
All-in build cost: $75K – $130K
Typical monthly rent: $1,100 – $1,550/mo
Build timeline: 4–6 months
How we deliver Junior ADU (JADU) Floor Plans Sacramento
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.
Stage 1 — Site walk and feasibility: setbacks, utilities, easements and lot coverage reviewed on site
Stage 2 — Fixed-scope proposal: line-item pricing with permits, utility connections and finishes included
Stage 3 — Design and engineering: architectural plans, Title 24 energy calcs and structural engineering
Stage 4 — Permitting and plan check: submittal, corrections and approvals handled by our office
Stage 5 — Construction and closeout: weekly updates, final inspection, certificate of occupancy and warranty
Common questions about Junior ADU (JADU) Floor Plans Sacramento
The three questions homeowners ask most, answered plainly. Pricing reflects 2026 Sacramento-region construction costs including permits, utility connections and standard finishes.
How much does an ADU cost? Most detached ADUs land between $135,000 and $255,000 all-in, depending on size and site conditions.
How long does it take? Design and permitting typically run 3–5 months; construction runs 4–7 months after permits are issued.
Do you handle permits? Yes — plan check submittal, corrections and inspections are managed in house at no extra hourly cost.
Can I rent it out? California state law allows ADUs to be rented at 30-day-plus terms in every jurisdiction we build in.
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.
CSLB #1094366 General Contractor · DRE #00898265 Broker
Serving Sacramento, Placer, El Dorado, Yolo and Sutter counties
In-house design, permitting, plan check and construction
4010 Foothills Blvd Ste 103-155, Roseville, CA 95747