Direct Answer
To hire a reliable commercial glass & curtain wall installation contractor in Columbia: (1) Get 3 written quotes with line-item breakdowns, (2) Verify MO license at Missouri Division of Professional Registration (pr.mo.gov), (3) Confirm active general liability and workers' comp insurance, (4) Check Google and BBB reviews specific to Columbia projects, (5) Never pay more than 10-30% upfront — never pay in full before completion.
Full Explanation
Red flags specific to Columbia contractors: no physical Columbia-area address, pressure to start immediately, cash-only payment demands, and license numbers that don't verify at Missouri Division of Professional Registration (pr.mo.gov). Seasonal demand during summer brings out less reputable contractors.
Local Factors in Columbia
📍Verify license: Missouri Division of Professional Registration (pr.mo.gov)
📍File complaints: Missouri Division of Professional Registration (pr.mo.gov)
📍Homeowner protections under MO consumer protection law
📍BBB Greater Columbia chapter for complaints history