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