#15 felt paper also known as tar paper is the standard underlayment for most roof installments. As an oil saturated compound, it covers approximately 432 sq. ft. of roofing area.
Dimensions: 3 ft. wide by 144 ft. long.
#30 Felt Paper
#30 felt is made of the same type of paper, but is twice as thick and twice as oil saturated for added water resistance. This roll covers approximately 216 sq. ft. of roofing area.
Dimensions: 3 ft. wide by 72 ft. long.
#75 Base Sheet
#75 base sheet is commonly used for no-slope roofs or commercial jobs. Unlike #15 and #30 felt, #75 base is granulated and porous for absorption of hot tar in commercial jobs. It covers approximately 316 sq. ft. of roofing area.