Roofers need commercial general liability (CGL) to cover claims like a leak or a fall from height. Many general contractors, property managers and homeowners ask for a certificate of insurance showing $2 million or more before work starts.
Beyond liability, roofing businesses usually need tools and equipment coverage, commercial auto for work vehicles, and in some cases coverage for materials and installations before the client accepts the job. Workers' compensation is separate and handled by your provincial board.