IDNLearn.com is designed to help you find accurate answers with ease. Join our knowledgeable community and access a wealth of reliable answers to your most pressing questions.

Generally, the roof underlayment used in steep roofs(asphalt shingles) is/are:
a. No. 15 asphalt-treated organic felt.
b. No. 10 asphalt-treated fiberglass felt.
c. No. 20 asphalt-treated organic felt