How to Choose an ADU Builder in Los Angeles

Choosing an ADU builder in Los Angeles is one of the most consequential decisions in the project — more so than choosing finishes or floor plans. The right builder reads your lot honestly, names the permit path, calls out the utility scope before signing, and writes a scope where every line is separated. The wrong one quotes from a photograph. This post walks through what to verify, what to ask, and what to listen for.

Verify the license first

Every legitimate ADU build in California requires a licensed general contractor. Start with the basics:

• CSLB license number, active and in good standing. Check at cslb.ca.gov — the license search is free and authoritative. Confirm classification covers general building (B).
• Workers' compensation coverage. Required by law for any contractor with employees. Ask for a current certificate of insurance.
• General liability insurance. Confirm coverage limits in writing.
• Bond. California requires a contractor's bond — verify it's current.

If a contractor hesitates on any of these, that's the answer.

Ask how they read your lot

A real ADU builder visits the property before quoting. On that visit they should:

• Look at the existing electrical panel and tell you what they see.
• Confirm the plumbing stack location and sewer lateral access.
• Note any structural walls in the way of layout changes.
• Check setbacks, slope, and access for heavy equipment.
• Identify whether the lot triggers any special review — hillside grading, HPOZ, coastal zone.

A contractor who can't answer questions about your specific lot after a site visit isn't ready to quote.

The permit path question

Most Los Angeles ADUs go through the state-mandated ministerial path at LADBS — faster and more predictable than discretionary review. But some lots fall under different rules. Ask:

• Is this ADU reviewable under the ministerial path on this lot?
• Are there overlays — hillside grading thresholds, HPOZ, coastal — that change the review?
• Does this property fall inside Beverly Hills, Culver City, Santa Monica, or West Hollywood, which run their own permit offices?

A builder familiar with LA neighborhoods names these up front. See our ADU permit guide for the broader process.

How to read a quote

A quote that lumps "cabinetry and countertops" or "MEP" into one line is a quote you can't actually compare. Insist on:

• Each line separated — foundation, framing, MEP, finishes, soft costs, permit fees.
• Soft costs (design, structural engineering, Title 24, permit fees) called out explicitly.
• A defined allowance for finishes, with what happens when you exceed it.
• A change-order process in writing.

If two builders quote different totals on the same lot, the answer is almost always in which lines are inside the number and which are separate.

References from real LA homes

Ask for recent ADU references in your neighborhood — or in similar lots (hillside, similar setbacks, similar permit office). Look at:

• Did the project finish at the price the contractor said it would, or did it slip on change orders?
• Did the project plan reflect honest selection lock, or did it assume picks during construction?
• Did the city inspections pass cleanly?

Drive by a finished build if you can. Material choices read very differently in person than in a photo.

What separates a real contractor from a sales pitch

A real ADU contractor will:

• Walk your lot before quoting.
• Name the permit path and any overlays.
• Hand you a written scope with each line separated.
• Lock cabinetry, stone, and appliance selection before demo starts.
• Provide a single point of contact and a written change-order process.
• Decline to give you a firm number from a photograph.

A sales pitch will:

• Quote a range over the phone.
• Lump line items together.
• Promise an implausibly fast turnaround.
• Push for a contract before you've reviewed the scope.

You'll know the difference within the first site visit.

Where Hillstar fits

Hillstar Construction is a licensed general contractor (CSLB #972213) building ADUs across Los Angeles — from the Westside through the San Fernando Valley. Detached, attached, garage conversion, JADU. We measure your lot, check the panel and stack, name the permit path, and produce a written scope where each line stands alone.

Local pages: Beverly Hills · Encino · Sherman Oaks · Woodland Hills · Studio City · Tarzana · Northridge.

For a deeper read on what actually drives ADU cost, see Complete ADU Cost Breakdown for Los Angeles Homes.

Frequently asked questions

How do I check a contractor's license in California?

Use the CSLB license search at cslb.ca.gov. Search by name or number, confirm the license is active, in good standing, and the bond and workers' comp are current. The check is free and takes a minute.

Should I get multiple quotes for an ADU build?

Yes — but make sure each contractor is quoting the same scope of work. Two quotes that look different on paper are often comparing different ADU types or different permit paths on the same lot.

What's a red flag when interviewing an ADU builder?

A firm number quoted from a photograph, a quote that lumps line items together, and any reluctance to share license / insurance / bond documentation. Reluctance is the answer.

Does Hillstar build outside Los Angeles?

Hillstar serves Los Angeles, Woodland Hills, Encino, Tarzana, Sherman Oaks, Studio City, Beverly Hills, Northridge, Chatsworth, West Hills, Van Nuys, Reseda, West Hollywood, Bel Air, and West Los Angeles.

Does Hillstar handle the permit submission?

Yes — design, structural engineering, Title 24, and permit submission are part of the scope. We handle LADBS or the applicable city office (Beverly Hills, Culver City, Santa Monica, West Hollywood each run their own).