On what slope can double-coverage roll roofing be used at a minimum?

Double-coverage roll roofing can be used at a minimum slope of 1 inch per foot. This type of roofing is designed for low-slope applications, and the 1-inch per foot minimum allows for effective water drainage. At this slope, the roofing material provides sufficient coverage and redundancy to prevent water infiltration, which is crucial given that flat and low-slope roofs are more susceptible to water pooling. Maintaining a minimum slope is important for ensuring proper drainage and the longevity of the roofing system.

Higher slopes, such as those in the other choices, typically exceed what is necessary for double-coverage roll roofing, as these materials are specifically meant for low-slope installations. Thus, the correct choice ensures that the roofing is applied effectively within its intended parameters.