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California contractor license

Sandstone Environmental Engineering Inc

Sandstone Environmental Engineering Inc of Oakley holds California license 878348 (A General Engineering, ASB Asbestos Certification, B General Building, C12 Earthwork and Paving, C21 Building Moving/Demolition, C22 Asbestos Abatement, HAZ Hazardous Substance Removal Certification). The CSLB file dated Oct 29, 2026 lists it as active.1 It expires Jul 31, 2028.

Licensed 20 years, longer than 82% of 64 active Oakley general contractors.

Active

Sandstone Environmental Engineering Inc, Oakley

License
878348
Class
A General Engineering; ASB Asbestos Certification; B General Building; C12 Earthwork and Paving; C21 Building Moving/Demolition; C22 Asbestos Abatement; HAZ Hazardous Substance Removal Certification
Expires
Jul 31, 2028
Bond
$25,000
Workers' comp
Insured to Jul 26, 2027

CSLB file dated Oct 29, 2026

From the CSLB file dated Oct 29, 2026. Not a consumer report; check the board before you hire.

What bond, insurance and workers' comp are on file?

Bond
$25,000Western Surety Company, from Jul 27, 2024, continuous
Liability insurance
Not in the CSLB fileCheck with the board
Workers' comp
InsuredState Compensation Insurance Fund, from Aug 25, 2026, to Jul 26, 2027

Who is on this license?

Responsible managing officer, CEO and president
Martin CastilloSince May 24, 2006

What work does this license cover?

Issued May 24, 2006. Reissued Jul 27, 2018.

Which other Oakley businesses hold A General Engineering?

California general contractors

What should you check before hiring?

What to ask before you hire

  1. Get the license number in writing. The name on the license should match the name on your contract and invoice.
  2. Check the class covers the job. A license for one trade doesn't cover another. California license classes
  3. Ask for a certificate of insurance sent to you by the insurance agent, not handed over by the contractor. How to read a COI
  4. Ask who will be on site. If a crew works on your property, ask for proof of workers' comp. An exemption on file means the contractor told the CSLB it has no employees.
  5. Put it in a written contract: license number, price, start date and payment schedule. Check the license again on the day you sign.

If the license is lapsed

  1. Don't sign or pay a deposit until the CSLB shows the license active again.
  2. Ask the contractor why. For a bond or insurance lapse, ask for proof that the new bond or policy was filed with the CSLB, then check again.
  3. If work has started, hold further payments, keep the contract, receipts and photos, and file a complaint with Contractors State License Board (CSLB).
  4. Check another contractor. California license lookup

Sources

  1. CSLB License Master (cslb.ca.gov, Oct 29, 2026)
  2. Contractors State License Board (CSLB)