ADU CITIES Contractor Directory

Cornerstone Construction Co

Also listed as: Baugh Richard L

● Active — license status verified against CSLB public data as of November 6, 2026

☎ Call (909) 861-7978Verify this license at CSLB
CSLB license#427183
ClassificationsB — General Building · C-9 — Drywall
Office of record1860 S Tintah Drive
Diamond Bar, CA 91765
Address as listed in the CSLB record — the office of record, not a service-area claim.
Phone (CSLB record)(909) 861-7978
Contractor bond$25,000 — Atlantic Specialty Insurance Company
Workers' comp (CSLB record)Exempt
Business typeSole Owner
License issuedAugust 26, 1982
License expiresAugust 31, 2028

Is this your business? Claim this listing to enhance it with your website, photos, and project details.

Data source: CSLB public records as of November 6, 2026. License status can change at any time — verify live at CSLB before signing a contract.