The answer to 'average cost of underlayment' is that the typical cost range for roofing underlayment can vary widely depending on factors like the type of underlayment, the size of the roof, and your local market. In general, you can expect to pay anywhere from $0.50 to $2.00 per square foot for basic asphalt-based underlayment, with higher-end synthetic options costing up to $3 per square foot or more. The underlayment is an essential layer that goes beneath the shingles, so it's important to factor this cost into your overall roofing project budget.
When getting quotes for a roofing job, be sure to ask your contractor about the type and cost of underlayment they recommend. The right underlayment can make a big difference in the durability and performance of your new roof, so it's worth considering quality and not just going with the cheapest option.