Cornerstone Construction Co

Diamond Bar · Los Angeles County · CA

Verified

Bestopedia verdict

93 / 100 Bestopedia Trust Score

California’s contractor board lists Cornerstone Construction Co with a license standing of CLEAR. A contractor bond is on file, and workers’ compensation coverage is current.

License standing
25 / 25
Clean record
15 / 15
Track record
25.7 / 30
License continuity
10 / 10
Workers' comp
9 / 12
Contractor bond
8 / 8

How the Trust Score is calculated →

The verified record

CSLB license
#427183 verify on CSLB ↗
Classifications
B, C-9
Years licensed
43.9 years since 08/26/1982
Contractor bond
$25,000 Hudson Insurance Company
Workers’ comp
Current
Business type
Sole Owner
Qualifying principal
Richard Lee Baugh
Address of record
1860 S Tintah Drive, Diamond Bar, CA 91765

Frequently Asked Questions

Is Cornerstone Construction Co a licensed General Contractor contractor in California?

Yes. Cornerstone Construction Co holds California CSLB contractor license #427183 with a B (General Building) classification. Current CSLB status: CLEAR (as of July 2026).

What work is Cornerstone Construction Co licensed to perform?

Cornerstone Construction Co is licensed for B (General Building), plus additional classifications: C-9.

Is Cornerstone Construction Co bonded?

Yes. Cornerstone Construction Co carries contractor's bond #30044171 for $25,000 through Hudson Insurance Company.

Does Cornerstone Construction Co carry workers' compensation insurance?

CSLB records list the workers' compensation status for Cornerstone Construction Co as Exempt.

How long has Cornerstone Construction Co held its contractor license?

Cornerstone Construction Co has held California contractor license #427183 since 08/26/1982, approximately 44 years (as of July 2026).

Where is Cornerstone Construction Co located?

Cornerstone Construction Co is based in Diamond Bar, Los Angeles County, CA 91765.