Two very different kinds of builder
When homeowners start searching for an "ADU contractor near me," they usually turn up two kinds of company: a general contractor who does kitchens, bathrooms, additions, and the occasional ADU, and an ADU specialist who builds accessory dwelling units week in and week out. Both may be perfectly licensed. But an ADU is a self-contained dwelling with its own rulebook, and that rulebook is where specialists pull ahead.
This guide explains where the differences actually show up — in law, in city processes, in utilities, and in how the project is delivered — so you can decide who should build yours. To pressure-test any candidate, run them through our 12-point vetting checklist.
What both should have
Before comparing, both types of contractor must clear the same baseline:
- An active CSLB B (General Building) license — verify it at cslb.ca.gov
- A current bond, general liability, and workers' compensation
- A verifiable project portfolio and consistent reviews
If a candidate can't clear these, the general-vs-specialist question is moot.
1. California ADU state law changes constantly
California has passed wave after wave of legislation reshaping what homeowners can build — size floors, setback minimums, parking exemptions, ministerial approval timelines, and more. An ADU specialist tracks these changes because their entire business depends on them. A general contractor who builds one ADU a year is far more likely to be working from outdated assumptions, and outdated assumptions get plans rejected at the counter.
2. Every city has its own quirks
State law sets the floor, but cities administer the process — and they don't do it identically. Plan-check preferences, required detail sheets, design review in certain districts, and inspection scheduling all vary. A specialist who has recently permitted in Sherman Oaks, Pasadena, Encino, North Hollywood, Woodland Hills, Santa Monica, or Calabasas already knows how each city likes to see a submittal. A generalist often learns those quirks on your project — and on your timeline.
3. Utility connections are an ADU-specific skill
Water, sewer, gas, and electrical connections are one of the most underestimated parts of an ADU. Questions like whether the ADU can share the main home's meter, how to size the electrical panel, where the sewer lateral ties in, and which utility requires a separate application are routine for a specialist and unfamiliar territory for a remodeler. Mistakes here cause expensive change orders and delays.
4. Title 24 and fire separation
California's Title 24 energy code and fire-separation requirements between an ADU and the main house are non-negotiable and specific to dwellings. A specialist bakes these into the design from day one. A generalist may treat them as an afterthought, triggering redesigns during plan check.
5. Design-build vs. hand-offs
Many ADU specialists work design-build — architecture, structural engineering, permitting, and construction under one roof. That matters because ADUs are small, tightly regulated projects where a mistake in design ripples straight into construction. When one team owns the whole process, there's a single point of accountability and far fewer costly hand-offs. A general contractor often relies on outside architects and permit expediters, adding coordination risk.
6. Speed to permit and predictability
Because specialists repeat the same project type, they have refined plan sets, known relationships with plan checkers, and internal permitting teams. That repetition tends to translate into a smoother path from design to permit to construction, with fewer surprises along the way.
When a general contractor can still be the right call
A general contractor may be a fine choice when your ADU is a straightforward garage conversion, the contractor has genuine, recent ADU completions, and they clear the same license, bond, insurance, and portfolio checks as any specialist. The key is recent ADU experience — not a general willingness to take the job. Always ask how many ADUs they completed in the last 12 months and whether any required a variance.
How to decide
- Confirm the license, bond, and insurance for either candidate.
- Ask specifically how many ADUs they completed in the last 12 months.
- Ask which cities they've permitted in — ideally yours.
- Ask who handles design, engineering, and permitting — one team or several.
- Compare portfolios of finished ADUs, like the projects in our portfolio.
For most homeowners, the ADU specialist's focus on state law, city quirks, utilities, and design-build delivery makes the process faster and more predictable. See where we build on our service areas page, review the full ADU contractor near me guide, and book a free site evaluation when you're ready.
Frequently Asked Questions
Is a general contractor allowed to build an ADU in California?
Yes, if they hold an active CSLB B (General Building) license in good standing. The license isn't the differentiator — recent, repeated ADU experience is. Always confirm how many ADUs they've completed in the last 12 months.
Why does ADU-specific experience matter so much?
ADUs carry rules that a kitchen or bathroom remodel doesn't: evolving state ADU law, city-specific plan-check quirks, utility connections, Title 24 energy compliance, and fire separation. A specialist handles these routinely; a generalist may learn them on your project.
What is design-build and why is it good for ADUs?
Design-build means architecture, engineering, permitting, and construction live under one roof with a single point of accountability. For small, tightly regulated ADU projects, it reduces costly hand-offs and keeps design and construction aligned.
How do I know if a contractor really specializes in ADUs?
Ask how many ADUs they completed in the last 12 months, which cities they permitted in, whether they handle permitting in-house, and to see a portfolio of finished ADUs. Cross-check their license and permit history using our vetting checklist.
Will a specialist really be faster than a general contractor?
Often, yes. Specialists repeat the same project type, so they use refined plan sets, have relationships with plan checkers, and run internal permitting — which tends to make the path from design to permit more predictable.
Should I still get multiple bids?
Yes. Get three bids on the identical scope of work, whether from generalists or specialists, and compare them on clarity and completeness — not just the headline number.