WHAT TO KNOW FIRST
We build four kinds of ADUs in Irvine. The right one depends on who will live there, where the new space can go, what the existing house can support, and how the work can reach the site.
- Detached ADUs create a separate backyard home.
- Garage conversions reuse a shell only after the structure is checked.
- Attached ADUs and JADUs change the main house in different ways.
Four ways to create a site-built ADU.
Detached and backyard ADUs
A new, separate building planned around yard use, access, foundation, utilities, drainage, and privacy.
Garage conversions
Living space created from an existing garage after its structure, slab, openings, services, moisture protection, and parking context are understood.
Attached ADUs
A unit connected to the primary residence, with a scope coordinated at shared walls, rooflines, utilities, structure, and household circulation.
Junior ADUs
A distinct project category created within the proposed or existing single-family residence, with its own size, facilities, and occupancy questions.
The estimate should cover more than the new rooms.
Look for access and staging, utility work, existing-structure repairs, drainage, finishes, permit coordination, inspections, and restoration. Our Irvine ADU construction process shows how these pieces move from the first walkthrough into drawings and construction.
Put open questions in writing.
The team may still need to investigate the slab, framing, electrical capacity, sewer route, title documents, survey, drainage, or association rules. The estimate should say who checks each item and what could change when the answer comes back.
Remember that you still live here.
Crews need a delivery path and a protected work area. Your family needs safe access to the main home. Driveways, gates, landscaping, security, dust, temporary shutoffs, and final yard repairs should be discussed before work begins.
Use the Irvine requirements guide to gather property details and the cost guide to compare proposals.
Tell us what you want the space to do.
Call (949) 763-5237 with the Irvine address, the ADU type you are considering, and any plans or photos you already have. The estimate checklist shows what helps. Return to Irvine ADU Contractor for the full local service overview.
PRIMARY SOURCES
Sources for Site-Built ADU Services in Irvine
Links checked September 7, 2026.
Before acting on site-built adu services in irvine, check the latest agency material and resolve open questions with the right professional.
RELATED IRVINE GUIDES
More on Site-Built ADU Services in Irvine
PLAN YOUR IRVINE ADU
Let’s look at what the work may involve.
A few home and site details will make a call about site-built adu services in irvine more productive.