On average, a homeowner will spend an average of $ 3.50 to 00 6.00 per square foot 350 to $ 600 per 100 square feet to replace the roof. The cost varies, depending on the type of material used, as well as the additional features that the roofing system requires. With so much money involved in installation and repair, it is ideal to take the necessary precautions to extend the life of your roof.