Remodeling & ADU Contractor in Tustin

Tustin has two very different sides when it comes to remodeling: the historic homes of Old Town and the planned neighborhoods of Tustin Ranch. IA Builders is a licensed California general contractor (CSLB #1124696) based in Culver City, and we handle remodels, room additions and ADUs in both. The approvals and the design approach change depending on which part of Tustin your home is in.

Old Town Tustin and the Cultural Resources District

Old Town Tustin includes the city's Cultural Resources District, an area with many of the city's oldest homes and buildings. Work there comes with an extra step. The City of Tustin requires a Certificate of Appropriateness for structures in the Cultural Resources District, and for designated cultural resources outside it. It is a no-fee permit, but it has to be obtained before, or at the same time as, the building permit for permitted work in the district.

In practice, that review focuses on whether exterior changes fit the historic character of the house and the street. For homeowners, it shapes decisions such as:

• How an addition is placed and scaled relative to the original house.
• Window, door, siding and roofing choices on visible elevations.
• The design of a detached ADU or garage behind a historic home.

The city has also adopted Residential Design Guidelines that address preservation alongside energy efficiency. We use those guidelines as a starting point so the design is on track before it goes to the city. Older Old Town homes also tend to need more behind the walls, from foundation and framing repairs to updated electrical and plumbing, and we plan for that in a whole-home remodel.

Tustin Ranch and newer neighborhoods

Tustin Ranch was once part of the Irvine Ranch. The Irvine Company began planning it in the early 1980s, the area was annexed to Tustin in 1986, and the neighborhoods were built out around the Tustin Ranch Golf Course in the years that followed. Homes there are now old enough that original kitchens, bathrooms and finishes are due for replacement, and many owners want to rework layouts that no longer fit how they live.

Many Tustin Ranch neighborhoods have homeowners associations with architectural guidelines, so exterior changes usually need association approval in addition to the city permit. We sequence those approvals so they run smoothly. A kitchen remodel inside the existing footprint is typically the simplest project to approve; additions and exterior changes take more coordination.

Permits in Tustin

Building permits and zoning review in Tustin go through the city's Community Development Department, with the Planning Division handling zoning, ADU standards and Cultural Resources District review. Tustin is inland, so the coastal development permits that affect projects in beach cities are not part of the process here. We prepare the drawings, submit them, respond to plan check comments and schedule the inspections.

ADUs in Tustin

The city amended its ADU rules in December 2021 through Ordinance 1517 to bring them into line with state law. Tustin allows attached, detached and converted ADUs as well as junior ADUs, with maximum sizes that depend on the number of bedrooms. In Old Town, an ADU in the Cultural Resources District also needs the Certificate of Appropriateness. In Tustin Ranch, state law prevents CC&Rs from prohibiting or unreasonably restricting an ADU on a single-family lot, though reasonable design standards still apply. We can help you weigh a detached unit against an ADU or garage conversion of existing space.

If you own a home in Tustin and are planning a project, call (213) 816-6465 or use the form on this page.

Frequently asked questions

Do I need special approval to remodel in Old Town Tustin?

If your home is in the Cultural Resources District, permitted work needs a Certificate of Appropriateness before or along with the building permit. It is focused on preserving historic character.

Can I add an ADU to a historic home in Tustin?

Yes, in many cases. An ADU in the Cultural Resources District goes through the Certificate of Appropriateness review, so its design should complement the main house.

Does my Tustin Ranch HOA need to approve my remodel?

For exterior changes, usually yes. Association approval is separate from the city permit, so we plan time for both.

Who reviews ADU applications in Tustin?

The Planning Division of the City of Tustin Community Development Department reviews ADU standards, and building plans then go through plan check.

Last reviewed October 2026