Skip to content
State files updated Oct 29, 2026
Look up a contractor
MenuClose

Home / License lookup / California / Duff & Sons Inc

California contractor license

Duff & Sons Inc

Duff & Sons Inc of Mammoth Lakes holds California license 1063434 (B General Building, C10 Electrical). The CSLB file dated Oct 29, 2026 lists it as active.1 It expires Feb 29, 2028.

Active

Duff & Sons Inc, Mammoth Lakes

License
1063434
Class
B General Building; C10 Electrical
Expires
Feb 29, 2028
Bond
$25,000
Workers' comp
Exempt

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
$25,000American Contractors Indemnity Company, from Apr 12, 2023, continuous
Liability insurance
Not in the CSLB fileCheck with the board
Workers' comp
Exemptfrom Apr 2, 2026

Who is on this license?

Officer
Alicia DuffSince Feb 18, 2020
Responsible managing officer, CEO and president
Grant K. DuffSince Feb 18, 2020

What work does this license cover?

Issued Feb 18, 2020.

The workers' comp exemption means the holder told the CSLB it has no employees. If a crew works on your job, ask for a workers' comp certificate.

Which other Mammoth Lakes businesses hold B General Building?

California electrical contractorsCalifornia 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)