R905.1.1(2) Underlayment Application
“For roof slopes of four units vertical in 12 units horizontal (4:12) or greater, underlayment shall be one layer applied in the following manner: underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches, Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be 4 inches and shall be offset by 6 feet.” Submitting a detailed report that highlights the adherence to building codes, the quality of materials used, and the installation process can help in appealing denied slopes. Arguing that you have to remove additional shingles on denied slopes to properly install the underlayment can be a useful tool in getting a full roof replacement covered.