Service Work. Re-Roofing. New Construction. GSM Roofing is a full service, fully credentialed commercial & specialty roofing contractor with proven expertise in multiple crafts and services to provide valuable solutions for almost every roof type. Our long history of excellence and professionalism sets us apart from other roofing contractors. Let us show you how the right roofing system and proper maintenance will help minimize the building’s expenses and help maximize business operations.