Overall, a roof replacement can be estimated to cost $2.50 to $5 per square foot for a built-up roof that features alternating layers of roofing materials, like tar or bitumen, waterproofing materials and roofing felt.
A single-ply roof, often lasting 20 to 30 years (depending on weather conditions) with its single layer, ranges from $3 to $4 per square foot.
A sheet metal roof, featuring interlocking panels of metal, steel or aluminum, averages $5 to $10 per square foot and is the most expensive choice of roofing material on the market.