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California / San Mateo / ADU builders

ADU builders in San Mateo, California

The short answer

15 licensed contractors building accessory dwelling units in San Mateo. Every licence below was checked against the California state register. San Mateo does not publish contractor names on building permits, so this list ranks on licence standing and pre-approved plans.

California Contractors State License Board, checked 2026-08-15
How to read this. Licence details come from the California Contractors State License Board and are dated on each profile. Permit counts reflect only those cities that publish the contractor's name on a building permit, so a builder with none listed may simply have worked where nothing is published. A city that pre-approves a plan has vetted the plan, not the builder, and does not endorse it. ADU Standards takes no payment for placement. Confirm any licence at cslb.ca.gov before you sign.

Ordered by what the records confirm

The list
1

S O D Home Group Inc

Nearby permits Licence clear 16 years licensed Workers’ comp on file

CSLB #942085 · SAN JOSE

3

Imkat Construction Corp

Nearby permits Licence clear 4 years licensed Workers’ comp on file

CSLB #1094866 · SACRAMENTO

5

Build 33 Inc.

Licensed Licence clear 7 years licensed Workers’ comp on file

CSLB #1051529 · CUPERTINO

8

Generation Builders Inc

Licensed Licence clear 3 years licensed Workers’ comp on file

CSLB #1101759 · BURLINGAME

9

Loona Construction Inc

Licensed Licence clear 3 years licensed No workers’ comp on file

CSLB #1095467 · NEWARK

10

Romy Construction Inc

Licensed Licence clear 3 years licensed Workers’ comp on file

CSLB #1104331 · SOUTH SAN FRANCISCO

11

Prada Builders Group

Licensed Licence clear 2 years licensed Workers’ comp on file

CSLB #1116392 · SAN JOSE

15

ADU San Mateo Llc

Licensed Licence clear 0 years licensed Workers’ comp on file

CSLB #1145539 · SAN MATEO

Common questions

How is this list ordered?

By what can be confirmed in public records: the number of accessory dwelling unit permits each contractor has on file in San Mateo, whether San Mateo has pre-approved their plans, and their licence standing with the California Contractors State License Board. No builder pays for position and none can request removal.

Are these builders licensed?

Every company listed has been matched to an active California contractor licence and its standing is shown on the card. California law requires a contractor to display its licence number in all advertising, and we check the number shown against the state register before publishing anything a company says about itself.

Why do some show no permit history?

Most California cities do not publish the contractor's name on a building permit. Where a city does not publish it, we cannot confirm completed work, so the card says the licence is verified and nothing more. Ask a builder directly for recent addresses and permit numbers you can look up.

What does it mean that San Mateo pre-approved a builder's plans?

Under Government Code section 65852.27 every California city must accept ADU plans for pre-approval and publish the resulting list. A pre-approved plan has cleared plan check in advance, which shortens permitting. It is an approval of the plan, not an endorsement of the company that drew it.

Four checks worth ten minutes.

Before you sign
  1. Look the licence up yourself at cslb.ca.gov. It takes under a minute and shows the current status, any suspensions, and the bond.
  2. Ask who carries workers’ compensation for the crew and for every subcontractor. A licensee with no employees may lawfully be exempt, but if someone is hurt on your property you can end up treated as the employer.
  3. Ask for two recent permit numbers in any city, then look them up. A builder who has done the work can produce them immediately.
  4. Get the price in writing against a drawing set. A published starting price is for a base model and rarely includes site work, utilities, or San Mateo fees.