Typically, a roof's slope cannot exceed one inch per foot. The pitch of the roof should be determined by the tiles to ensure proper drainage of water after rainstorms. For a single-family dwelling, most building departments require a minimum slope of 3/12 or greater. For areas that are highly prone to wildfires, a 6/12 slope is recommended. Different roofing materials have different weight and water drainage requirements, so it is important to factor all of this in when making your selections.