What is an ADU and why should I build one?

An Accessory Dwelling Unit (ADU) is a secondary residential unit on a single-family or multi-family lot. ADUs provide flexible living space for family members, generate rental income ($1,500–$3,500/month in the Sacramento area), and increase property values by 20–35%. California law now allows ADUs on virtually all residential properties.

How long does ADU construction take from start to finish?

A typical ADU project takes 8–14 months total. This includes 4–6 weeks for design, 4–8 weeks for permitting, and 4–6 months for construction. Garage conversions and JADUs are faster — often 2–4 months of construction. Timeline varies based on unit size, complexity, and local permit processing times.

Do I need to live on the property to build an ADU?

No. Under current California law, there is no owner-occupancy requirement for most ADU types. You can build an ADU and rent both the primary home and the ADU. Some jurisdictions have specific rules for JADUs, so we'll clarify requirements during your consultation.

What permits are required for ADU construction?

ADU construction requires a building permit from your local jurisdiction (city or county). This includes plan review for structural, electrical, plumbing, mechanical, and energy compliance. Some projects may also require grading permits, sewer connection permits, or fire department review. We handle all permit applications and inspections as part of our service.

Can I finance my ADU construction?

Yes. Common ADU financing options include home equity loans (HELOCs), cash-out refinancing, construction loans, and personal loans. Some homeowners also use CalHFA's ADU Grant Program, which provides up to $40,000 for qualifying projects. We can connect you with lenders experienced in ADU financing.

ADU Construction Specialists

ADU Construction Specialists — quick facts

Greater Sacramento's ADU & space-conversion specialists. Detached, attached, JADU & garage-to-ADU. CSLB #1094366. Call (866) 797-7653. A1 Building Contractors LLC is a veteran-owned, licensed general contractor serving the greater Sacramento region. Every project starts with a review of the property, the local jurisdiction and the homeowner's goals.

Licensed California general contractor — CSLB #1094366, DRE #00898265.
Veteran-owned and based in Roseville, serving Sacramento, Placer and El Dorado counties.
Scope covers detached ADUs, attached ADUs, JADUs, garage conversions, home additions and custom homes.
Plans, permits, plan check and construction are coordinated in-house for ADU Construction Specialists.
Typical detached ADU budgets run about $135K to $255K depending on size and site conditions.

Local guidance for ADU Construction Specialists

A1 Building Contractors LLC helps Sacramento-area and Placer County homeowners evaluate design, permitting, site access, utilities, construction scope and realistic project costs before work begins. Each project is reviewed against the property, local jurisdiction and homeowner goals rather than a one-size-fits-all estimate.

For ADU Construction Specialists, our team can explain practical options, likely approval steps and the tradeoffs that affect schedule and budget. Homeowners receive a clear path from initial feasibility through plans, permits and construction, with recommendations grounded in local building requirements and build conditions.

A productive first review considers available lot space, setbacks, access for construction, utility locations, desired square footage and long-term use. Those details help identify constraints early, compare appropriate project approaches and avoid spending on a design that does not fit the site or local rules. A1 then coordinates the applicable design and construction stages with clear decisions at each milestone.

Greater Sacramento ADU Construction Specialists

Accessory Dwelling Unit construction has become one of the most sought-after home improvement investments in California, and the Greater Sacramento region is leading the charge. At A1 Building Contractors, we provide complete, turnkey ADU construction services that cover every phase of the project — from initial feasibility analysis and custom architectural design through local permitting, site preparation, and full construction. Our team has built dozens of ADUs across Sacramento County, Placer County, El Dorado County, and Yolo County, giving us deep, hands-on knowledge of the unique building codes, zoning regulations, and permit processes in each jurisdiction.

We are a CSLB-licensed (#1094366), veteran-owned general contractor with in-house crews who handle foundation, framing, roofing, plumbing, electrical, HVAC, insulation, drywall, cabinetry, flooring, and finish work — no unreliable subcontractor chains. Whether you want to build a detached backyard cottage for rental income, an attached in-law suite for aging parents, or a Junior ADU carved out of existing interior space, our experienced team delivers quality construction on schedule and within budget. We understand that building an ADU is a significant financial decision, which is why we provide transparent, fixed-price proposals with no hidden fees or surprise change orders.

California's progressive ADU legislation — including AB 68, AB 881, SB 9, and AB 1033 — has dramatically simplified the process of adding a secondary dwelling to residential properties. Impact fees are waived for units under 750 square feet, setback requirements have been reduced to just four feet for detached structures, and owner-occupancy requirements have been suspended for most ADU types. These regulatory changes, combined with the Sacramento region's strong rental market and rising property values, make ADU construction one of the smartest investments a homeowner can make today.

A well-built ADU in the Sacramento area typically increases property value by 20–35% while generating $1,500–$3,500 per month in rental income depending on location, size, and finishes. Our construction quality, attention to detail, and commitment to client satisfaction have earned us a reputation as one of the region's most trusted ADU builders. We serve homeowners in Sacramento, Roseville, Rocklin, Folsom, Elk Grove, Citrus Heights, Rancho Cordova, Lincoln, Auburn, Granite Bay, El Dorado Hills, Davis, Woodland, Orangevale, Fair Oaks, Galt, and Wilton.

Detached ADUs — custom backyard cottages up to 1,200 sq ft with full kitchens, bathrooms, and living areas
Attached ADUs — additions built directly onto your existing home, sharing one or more walls
Junior ADUs (JADUs) — conversions of existing interior space (bedrooms, bonus rooms) up to 500 sq ft
Garage-to-ADU conversions — transforming existing garages into fully permitted living units
Two-story ADUs — maximizing smaller lots with vertically designed units
Multi-unit ADU projects — building multiple ADUs on qualifying multi-family parcels
Service area: Sacramento Region, Sacramento & Placer Counties

ADU Construction Specialists in Sacramento Region

The Greater Sacramento region is experiencing unprecedented ADU construction activity. Sacramento County alone has issued over 2,800 ADU permits since 2020, and Placer County is seeing similar growth. California's housing shortage — estimated at 3.5 million units statewide — has made ADUs a critical part of the state's housing strategy, which is why legislators continue to pass laws making ADU construction easier and more affordable.

For Sacramento-area homeowners, the financial case for building an ADU has never been stronger. The region's median rent for a 1-bedroom unit exceeds $1,500/month, and well-appointed ADUs in desirable neighborhoods command $2,000–$3,500/month. Meanwhile, a professionally built ADU typically adds $150,000–$300,000 to a property's appraised value — often exceeding the construction cost itself.

Popular ADU configurations in our region include 600–800 sq ft detached cottages with one bedroom, one bathroom, and an open-plan kitchen/living area. These units appeal to a wide range of tenants — young professionals, retirees, traveling nurses, and remote workers — ensuring consistent occupancy and reliable income. Larger families often opt for 1,000–1,200 sq ft two-bedroom units that can house aging parents, adult children, or generate premium rental income.

ADU Construction Costs in the Sacramento Region

ADU construction costs in the Greater Sacramento area depend on unit type (detached vs. attached vs. JADU), size, site conditions, foundation type, and finish level. Below are realistic 2025–2026 price ranges based on our completed projects across Sacramento, Placer, El Dorado, and Yolo Counties. All prices include design, permits, and complete construction.

Studio / 1-Bed ADU (400–600 sq ft): $90,000 – $175,000
2-Bedroom ADU (600–800 sq ft): $140,000 – $240,000
Large ADU (800–1,200 sq ft): $200,000 – $360,000
Junior ADU (JADU, interior conversion): $50,000 – $100,000
Garage-to-ADU Conversion: $60,000 – $130,000
Per Square Foot (new construction): $180 – $300

Our ADU Construction Process — Start to Finish

Each stage below has a defined deliverable, so you always know what is happening and what comes next.

Free Property Assessment — We visit your property to evaluate lot size, setbacks, utility access, soil conditions, and zoning. We discuss your goals — rental income, family housing, home office — and provide an honest assessment of what's feasible and what it will cost. This consultation is completely free with no obligation.
Custom Design & Engineering — Our in-house architects create detailed plans tailored to your lot, lifestyle, and budget. We handle structural engineering, Title 24 energy compliance calculations, and material specifications. You'll see 3D renderings of your ADU before construction begins, and we refine the design until you're 100% satisfied.
Permit Acquisition — We prepare and submit complete permit applications to your local building department — Sacramento County, Placer County, El Dorado County, or Yolo County. Our team manages plan check revisions, coordinates with planning and fire departments, and secures all necessary approvals. Our established relationships with local permitting offices help expedite the process.
Site Preparation & Foundation — Construction begins with site grading, trenching for utilities, and foundation work. Depending on your ADU type, this may include a concrete slab, raised foundation, or pier system. We connect sewer, water, gas, and electrical services and ensure proper drainage around the new structure.
Framing, Roofing & Exterior — Our crews frame the structure, install roof trusses or rafters, apply sheathing and weather barriers, and complete exterior finishes including siding, stucco, or board-and-batten to match your existing home. Windows and exterior doors are installed during this phase.
Mechanical Systems — Licensed plumbers, electricians, and HVAC technicians install all mechanical systems — water supply and drain lines, electrical panels and wiring, heating and air conditioning, and ventilation. All work is inspected and approved before closing walls.

Frequently asked: ADU Construction Specialists

The questions homeowners ask most about this service, answered by a CSLB-licensed Sacramento-region builder.

What is an ADU and why should I build one? An Accessory Dwelling Unit (ADU) is a secondary residential unit on a single-family or multi-family lot. ADUs provide flexible living space for family members, generate rental income ($1,500–$3,500/month in the Sacramento area), and increase property values by 20–35%. California law now allows ADUs on virtually all residential properties.
How long does ADU construction take from start to finish? A typical ADU project takes 8–14 months total. This includes 4–6 weeks for design, 4–8 weeks for permitting, and 4–6 months for construction. Garage conversions and JADUs are faster — often 2–4 months of construction. Timeline varies based on unit size, complexity, and local permit processing times.
Do I need to live on the property to build an ADU? No. Under current California law, there is no owner-occupancy requirement for most ADU types. You can build an ADU and rent both the primary home and the ADU. Some jurisdictions have specific rules for JADUs, so we'll clarify requirements during your consultation.
What permits are required for ADU construction? ADU construction requires a building permit from your local jurisdiction (city or county). This includes plan review for structural, electrical, plumbing, mechanical, and energy compliance. Some projects may also require grading permits, sewer connection permits, or fire department review. We handle all permit applications and inspections as part of our service.
Can I finance my ADU construction? Yes. Common ADU financing options include home equity loans (HELOCs), cash-out refinancing, construction loans, and personal loans. Some homeowners also use CalHFA's ADU Grant Program, which provides up to $40,000 for qualifying projects. We can connect you with lenders experienced in ADU financing.

Why Choose A1 Building Contractors for ADU Construction

A1 Building Contractors LLC is a veteran-owned, CSLB-licensed general contractor based in Roseville, CA, building across Sacramento, Placer, El Dorado, Yolo and Sutter counties.

Veteran-owned company with military-grade discipline, integrity, and attention to detail in every project
CSLB Licensed (#1094366) with comprehensive general liability and workers' compensation insurance
True turnkey service — one contractor, one point of contact from first consultation through move-in day
In-house crews for framing, finish carpentry, and project management — no unreliable subcontractor chains
Deep expertise in Sacramento County, Placer County, El Dorado County, and Yolo County building codes and permits
Transparent, fixed-price contracts with no hidden fees, surprise change orders, or cost escalations
10-year structural warranty on every ADU we build, plus manufacturer warranties on all materials and systems