The cost of a new roof in Hamilton depends on the size of the roof, the material being installed, the pitch and complexity of the structure, and whether any decking or flashing repairs are needed during the replacement. A straightforward shingle roof replacement will cost less than a more complex project involving multiple rooflines, steep slopes, or low-slope sections. The best way to get an accurate number is with an on-site inspection and written quote based on the actual condition of the roof.