Sectional Garage Doors Sectional garage doors made of two layers of steels and polyurethane foam insulation. Top Dog sectional doors come with its build in strut that can provide highest pressure & wind resistance. It can reach to 36 feet wide.   FEATURE Door Construction  3 layer construction  Panel Thickness  2’’  Exterior & Interior Steel  26-Gauge  Insulation Type  Polyurethane  Warranty  Limited Lifetime R-Value 15.2   COLORS White   Steel Insulated Garage Door, Aluminum Alloy High Speed Hard Door, Aluminum Exterior Door Exporter Canada. Top Dog main products：high speed hard commercial door, sectional garage door and high speed fabric garage door. Top Dog’s commercial door can apply to industrial area, storage, restaurants, retail centers, and automotive service centers. The newest generation of Top Dog commercial doors can offer the ultimate in strength, security and safety.