Roofing contractors usually add 10 to 15% to the total square footage of the roof to account for the waste factor, but this calculation can vary depending on the roof style or roof materials. In the case of roofs, the waste factor takes into account the material that is superimposed on the valleys and the hips, as well as the material cut around the joints, penetrations and ends of the gables. In terms of resistance to heat and hail, metal roofs are the best option. Asphalt shingles are a great option for those with lower budgets.
Something that many people are surprised to learn when they start researching roofing needs is that roofers have their own measurement unit, the square of the roof. It's crucial that the roofer doesn't stop replacing attic fans or other ventilation components, as needed, when finishing a roofing job.
