Cornerstone Windows & Patio Doors

CLOSED IN 2026. Located in Torrance, CA, Cornerstone Windows has serviced the South Bay of Los Angeles since 1999, specializing in replacement windows, folding/multislide doors, sliding glass patio doors, custom entry doors, and custom french doors. Most projects take only one day. Cornerstone employs ONLY full- time employees, which guarantees the highest level of quality control on all projects. Cornerstone is fully licensed, bonded and insured.