Corner Keystone Construction Corporation

Corner Keystone Construction Corporation holds license number 992459 issued by the Contractors State License Board. The classifications under this license are B – General Building Contractor and C-33 – Painting and Decoration Contractor. Our company was established on April 28, 2014 and we are located at 340 S Lemon Avenue, Suite 5210, Walnut, California 91789.

Our company provides an array of construction services in Southern California such as San Diego, Los Angeles, Orange, San Bernardino, Riverside, and San Luis Obispo counties. We propose different solutions to your residential, commercial, public works, either horizontal or vertical structural needs, catering not just to the industry’s standards but also to the client’s budget as well. Tailored to suit your needs, rest assured that the quality and service we render will fit your desires and will meet your expectations. We offer a competitive package price, assuring you of superb workmanship from start to completion of the project.

Our company’s mission is to be recognized as one of California’s best General Building contractors, operating with passion and professionalism while providing high standard projects. We continue to strive to fulfill and surpass expectations of our clients while maintaining harmonious relationships with and among clients, owners and employees.


To be recognized as one of California’s best construction companies working with passion and professionalism while providing high standard projects.


Corner Keystone Construction Corporation’s mission is to undertake as successfully complete construction jobs for residential, commercial and public works vertical and horizontal structures, satisfying the set forth standards and constantly exceeding our client’s expectations.

Accreditation and Certifications

EPA-RRP Certified: NAT-F123129-1 Expiry 05/29/2019
California Small Business Certified: Supplier # 1783800 Expiry 04/30/2018
Energy Upgrade California – Energy Modeling: Certified 05/30/2014
Energy Upgrade California – Combustion Safety: Certified 05/30/2014

Insurance Information and Limits

General Liability

  • $1,000,000 per occurrence
  • $100,000 to rented premises
  • $1,000,000 personal and adv injury
  • $2,000,000 General aggregate.

Insured by: Atain Specialty Insurance Co, Policy Number: CIP314804

Automobile Liability

  • $1,000,000 combined single limit

Insured by: Security National Insurance Co, Policy Number: SPP111499803

Worker's Compensation

  • $1,000,000 per accident.

Insured by: Benchmark Insurance Company, Policy Number: CST5010242