Ontario\'s Best Roof, official installer of the Interlock Roofing System in Ontario, Canada. Interlock Industries (Ont) Inc. is one of the largest installers of residential and commercial metal roofing systems in Ontario. Offering installation and financing options for flat to steep roofs. Choose from slate, shingle, shake, tile, standing seam or flat membrane roofing profiles. Available is many designer colours including Aged Copper and Weathered Grey. All aluminum roofing systems are coated with the Alunar Coating System embedded with TEFLON surface protector.