The answer to 'average cost of flat roof' is that the typical range for a flat roof installation can vary widely, depending on several factors. Generally, homeowners can expect to pay anywhere from $5 to $20 per square foot for a flat roof, with the average cost being around $10 to $15 per square foot.
The final cost will depend on the size of the roof, the materials used (such as single-ply membrane, built-up roofing, or modified bitumen), the complexity of the installation, and the location of the home. Homeowners should get multiple quotes from local roofing contractors to get the best price for their specific project.