How to hire a garage conversion contractor in San Diego

Hiring for a garage conversion is different from hiring for a remodel

A garage-to-ADU conversion is not a simple interior renovation. It is a project that touches nearly every trade (framing, plumbing, electrical, HVAC, finishes), runs through a multi-month permit process with your local building department, and produces a structure that will either legally add value to your property or create a problem you will have to explain at resale.

The contractor you hire is doing more than swinging hammers. They are your permit agent, your subcontractor coordinator, your construction manager, and your single point of accountability for a project that will cost $50,000-$150,000 and take 9-18 months from planning to occupancy. Hiring someone who does not have the experience, the license, or the track record for this specific type of work is the most common source of failed ADU projects in San Diego.

Here is how to hire correctly.

Start with license verification

California requires a contractor’s license for any project over $500 in labor and materials. For a garage conversion, you want a General Building Contractor (B license) or, if the contractor is doing specialty trade work themselves, the appropriate specialty license (C-20 for HVAC, C-36 for plumbing, C-10 for electrical).

Verify every contractor’s license at cslb.ca.gov before any conversation about money or signing anything. Check three things:

Active license status. The license must show as active. A recently expired or suspended license is a disqualifying finding, not a minor issue.

Workers’ compensation insurance. If the license shows “exempt” for workers’ comp, the contractor works alone with no employees and should not be bringing on subcontractors under their license. Most garage conversion contractors carry workers’ comp because they have employees or regular subcontractors. Ask for a certificate of insurance.

Complaint and discipline history. The CSLB license lookup shows disciplinary history. One nuanced complaint from years ago may be less significant than multiple recent complaints.

What to ask about ADU and garage conversion experience

Not every contractor with a B license has done ADU conversions in San Diego. This is a specific type of project with specific permit pathways, and experience matters.

Ask directly:

“How many garage conversions to ADUs have you completed in San Diego County in the last three years?”

If the answer is fewer than five, they are relatively new to this work. That is not necessarily disqualifying if they have strong general contractor experience and a thoughtful process, but you should understand what you are taking on.

“Have you permitted projects in [your specific city]?”

Each San Diego city has its own building department and its own quirks. A contractor who has permitted in Chula Vista but not in Escondido may not know that Escondido’s plan check process runs longer and has different comment patterns. Experience in your specific jurisdiction is worth asking about.

“What is your typical plan check timeline for a project like mine?”

A contractor who has done this work can give you a realistic estimate based on current department wait times. A contractor who says “two to three months” without qualification when actual City of San Diego wait times are 4-8 months is either inexperienced or not telling you the truth.

“Do you handle the permit process yourself or do you use a permit expediter?”

Both approaches are valid. A contractor who does permit expediting in-house tends to have tighter feedback loops. One who uses an expediter may still have good results if the expediter is experienced.

Insurance requirements

Before signing a contract, get certificates of insurance for two policies:

General liability insurance. This protects you from property damage and bodily injury claims arising from the contractor’s work on your property. A minimum of $1,000,000 per occurrence is standard for a San Diego garage conversion. The certificate should name you as an additional insured.

Workers’ compensation insurance. This covers injuries to the contractor’s employees or subcontractors while working on your property. Without it, an injured worker can potentially make a claim against your homeowner’s policy. Ask for a certificate showing current coverage.

If the contractor says they do not carry one of these policies, that is a hard stop. Do not proceed.

How to compare quotes

Get three written quotes minimum. Comparing garage conversion quotes requires more than looking at the bottom line.

Scope of work. The most useful comparison is whether each quote covers the same scope. If one quote includes permit fees and two do not, you are not comparing the same thing. If one quote includes the subfloor and two describe it as a line item “TBD,” you will have a surprise.

Ask every contractor to include the permit and plan check fees (even if estimated), subfloor system, window and door work, insulation, HVAC (system and installation), electrical (panel upgrade if needed, plus circuits), plumbing, drywall, paint, and finishes as separate line items. Then compare line by line.

Product specifics. If one contractor is spec’ing a Mitsubishi mini-split and another is quoting a no-name brand, that is a real difference. Ask for the manufacturer and model on HVAC, windows, and any other major equipment.

Permit and inspection handling. Confirm that the quote includes the contractor pulling the permit in their name, coordinating all inspections, and managing the certificate of occupancy process.

Payment schedule. A common structure for a project this size is 10% down, 25% at permit issuance, 25% at rough framing completion, 25% at drywall completion, and 15% on final occupancy. Be cautious of any contractor requesting more than 30% upfront. California law limits contractor deposits to 10% or $1,000, whichever is less, for most residential projects.

Red flags to recognize

No written contract. Everything should be in writing. A verbal agreement is not a contract for a project of this size.

Permit described as optional. Any contractor who suggests you can skip the permit and have it added later, or who implies the city won’t find out, is telling you to expose yourself to significant legal and financial risk.

The quote is dramatically lower than others. A quote that is 30-40% below comparable bids almost always reflects missing scope, unlicensed subcontractors, or a contractor who will ask for more money once you are committed.

Cannot provide references from completed San Diego ADU projects. Ask for three references with contact information and call them. Ask specifically about permit timeline accuracy, communication during the project, and whether the final cost matched the quote.

Pressure to sign quickly. A legitimate contractor does not need you to sign today. If there is pressure to commit before you have checked the license, reviewed insurance, and compared bids, that pressure is itself a signal.

Using a referral service

Garage Convert SD connects San Diego homeowners with experienced, insured local crews who specialize in garage conversions. We are a referral service, not a contractor. When you call us, we match you with vetted contractors in your area based on your project type and jurisdiction. You verify the license and insurance directly, get quotes, and make the hiring decision. Our number is (858) 925-5546.

More information is on the garage conversion service page. Verify any contractor’s license at cslb.ca.gov before signing a contract.

What license does a garage conversion contractor need in California?

A B (General Building) license is the most common. Contractors doing specialty trade work themselves (plumbing, electrical, HVAC) need the corresponding C license for those trades or must use licensed subcontractors.

Can a contractor without a license do a garage ADU conversion in California?

No. California law requires a contractor’s license for any project over $500. A contractor without a valid CSLB license cannot legally pull permits, which means the work cannot be inspected or certified as code-compliant. This exposes you to both financial and legal risk.

How much should a deposit be for a garage conversion in San Diego?

California law generally limits contractor deposits for home improvement contracts to 10% of the contract price or $1,000, whichever is less. For projects over $10,000, a higher initial payment may be structured as a first progress payment rather than a deposit, which is permitted under the law.

Should I get a fixed-price or cost-plus contract for a garage conversion?

Fixed-price (lump-sum) contracts are generally better for homeowners because they define the total cost upfront and put the risk of cost overruns on the contractor. Cost-plus contracts are common for renovations with high uncertainty, but garage conversions are well-defined enough that a fixed price with a defined change order process is the standard and preferred approach.

To get connected with vetted local crews, see our design consultation service page for a no-pressure first step.