Best ADU Builders in San Jose, California

If you are building in the South Bay or on the Peninsula and you want the safest pair of hands, this is it. The license goes back to February 1992, which is the longest unbroken record on this page by fifteen years, and it holds up clean: active B-General through March 2028, bond on file, workers comp current. That 1992 date also does something rare in this trade, which is back up the marketing. When Acton says thirty-plus years, the state’s own record agrees.

What I like operationally is that they build site-built ADUs from a curated set of pre-designed plans and they are explicit that this is not prefab. That distinction gets deliberately fuzzed by half this industry. A pre-designed plan set that a plan checker has seen before moves faster than a bespoke set, and you get that speed without giving up a foundation poured on your actual lot.

The review record has improved since I last checked, and I would rather correct myself than leave a stale gap on the page. Google now reads 5.0 across 44 reviews and Houzz reads 4.9 across 31, both read live on August 9, 2026, with 22 more on Yelp. An earlier pass of mine found no verifiable Google presence at all. Two independent platforms in agreement at the top of the scale, on a license that goes back to 1992, is about as much corroboration as this trade offers.

Nobody in San Jose has a deeper review record. 146 Google reviews at 4.8 is roughly 60 percent more than the next builder on this page, and the license has been clean since December 2015: no complaint disclosure, no bond cancellation, workers comp current through October 2026. On the two things I can check independently, they check out.

The caveat is about what those reviews are actually measuring. Google files them as a general contractor, not an ADU specialist, and their service list runs across ADUs, garage conversions and attached units alongside broader remodeling. So the review base covers more than the work you would be buying. That is not a knock, and honestly a remodeler who has spent a decade inside Santa Clara County permitting is worth something specific. It just means 146 reviews is not 146 ADUs.

If you are converting rather than building new, I would put them near the top of your call list. Conversion work rewards the exact experience a busy remodeler accumulates, and their license covers it without subcontracting the structural piece.

If your lot is in Los Altos, Saratoga, Palo Alto or the wealthier edges of San Jose, this is the builder I would call first. The 4.9 across 73 Google reviews is the best rating-to-volume combination in the market, and the license is clean: issued December 2022, bond current, workers comp current, no complaint disclosure anywhere on the record.

What I like is that their service area is honest. They name nine cities in a tight corridor from Atherton down through San Jose instead of claiming the entire Bay Area the way half this industry does. A builder who tells you where they do not work is telling you something useful about how they schedule crews.

Two things to weigh. The license is three and a half years old, so the depth of record you get from someone like Acton is not there yet. And they run their own “best ADU builders in San Jose” listicle, which you may well land on while researching. I would read that for what it is. A builder ranking its own competitors is marketing, not methodology, and it is worth knowing which one you are reading.

Eighty-seven Google reviews at 4.8 puts OT Bay second only to Wise Builders on review depth in San Jose, and the operating picture is sound: San Jose address, bond current since March 2024, workers comp current, and a qualifying individual who owns 10 percent or more of the company, which is the arrangement you want because it ties the license holder’s money to the work.

Then there is the thing I am not going to bury. CSLB carries complaint disclosure information on license 1097881. That is a specific status flag the board attaches when a license has public complaint history, and it is not the same as a suspension, a citation, or any finding against them. Plenty of good contractors pick one up. But it is public, this page exists to surface exactly this kind of detail, and you should ask them about it on the first call rather than find out later.

I would still shortlist them. A four-year-old license with 87 reviews at 4.8 in a market this expensive is a real signal, and a builder who answers the complaint question straight is often more informative than one who has never had to.

IMKAT is the one I would look at for a custom stick-built ADU that is not a catalog product, and they do it at a volume most boutique firms cannot. The license is clean: active B-General, issued August 2022, good through August 2028, workers comp current into 2027. Well, sort of clean. The company presents itself as founded in 2016, and the license doing the work today was issued in 2022, which is a gap worth asking about rather than assuming.

One item changed when I re-read the record on August 9, 2026, and it is the first thing I would raise with them. Their contractor’s bond now carries a cancellation date of September 2, 2026. A contractor’s bond is what keeps the license active, so if that date passes without a replacement filed, an active license becomes a suspended one and your build stops. It may well be a routine carrier switch. Ask, and ask before you sign anything.

Here is the other honest caveat, and it is the reason they are not higher. The aggregate rating is 4.9, but it sits on a thin independent base, and BBB carries real complaints including a delayed or abandoned project and a retaining-wall permit dispute. A high average on ninety-odd reviews does not cancel out a specific homeowner who got left mid-build. If you are going to hire them, ask for three recent Sacramento addresses you can drive past and two homeowners you can actually call.

Villa is the prefab option I can actually stand behind on paper, and the reason is a detail most comparison pages miss. Their license carries a C47 Manufactured Housing classification alongside the B-General, which is the classification a prefab builder is supposed to hold, and plenty of companies selling “modular” ADUs do not have it. Active since July 2021, bond and workers comp both current when I checked.

The catch is that there is almost nothing to read. No Google presence I could verify, no Yelp record, no Houzz. For a company founded in 2019 that is unusual, and it means you are buying on the strength of the product and the paperwork rather than on other homeowners’ experiences. If predictable pricing and a fixed scope matter more to you than a thick review file, that trade is defensible. Just go in knowing you are making it.

One housekeeping note. When you look Villa up yourself you may hit a second record, #1139781, registered as a sole ownership at the same San Francisco address and marked inactive. That is not the operating license. The one doing the work is #1077688.

Samara is the design-forward end of Bay Area prefab. Five sizes up to about 950 square feet, all-electric, fire-resistant, and a genuinely considered product rather than a shed with a kitchen in it. The license verifies clean: active B-General since March 2023, bond effective April 2026, workers comp running through April 2027.

One licensing detail worth understanding, because it separates the two prefab options on this page. Villa carries C47 Manufactured Housing alongside its B classification. Samara holds B only. That is not a violation and it does not make them unlicensed, it reflects a different delivery model, but if you want the classification the state specifically maintains for factory-built housing, Villa is the one that has it. Ask Samara directly how their units are certified and who signs off on the factory work.

There is also a date on the record I would want answered before signing. Their Bond of Qualifying Individual carries a cancellation date of September 2, 2026. That bond exists because the qualifying individual no longer owns 10 percent or more of the company, which is the condition that normally waives it. If it cancels without a replacement on file, the license goes into suspension for lack of a qualifier bond. Most of the time this is a carrier change and nothing happens. Check it anyway.

The other thing to hold in your head is what the published price actually covers. Roughly $314 per square foot in 2026 is unit-only. Foundation, site work, utility runs and installation land on top, and on a difficult lot that gap is not small. I would rather they published a delivered range, but publishing anything at all puts them ahead of most of this category.

Aldy is here because the record is clean, and last because the evidence is thin. The license has been active since December 2017 with no complaint disclosure, no bond cancellation, a bond refreshed in March 2025 and workers comp running through December 2026. On paper there is nothing to object to.

The 5.0 rating, though, rests on eight reviews. I want to be blunt about that, because a perfect score is the easiest number on a page like this to misread. Eight reviews is a sample, not a reputation. Two unhappy customers would take that to 4.0 overnight, and the same two would barely move Wise Builders. Treat the rating as unproven rather than excellent.

Where a shop this size genuinely wins is attention. Family-run means the person who prices your job is plausibly the person standing on it, and on a garage conversion that continuity is worth real money. Google files them as a kitchen remodeler, so ask directly how many ADUs they have finished in Santa Clara County and get addresses. If the answer is solid, the size stops being a risk and starts being the reason to hire them.