Minimum Slope for Roofing Shingles

June 2, 2015

What is the minimum slope for a shingle roof?

To ensure shingles function effectively, proper roof slope is essential. The minimum slope requirement for shingle roofs is 2/12, which means there should be a rise of two units for every twelve units of horizontal distance. This translates to approximately nine degrees. Even if an installer does an excellent job, a roof with inadequate slope, like the garage shown in the photo above, may experience issues. This minimum slope guideline is commonly found in installation instructions from most manufacturers and is often included in building codes.

Normal Roof Slope for Shingle Installation

For typical installations, shingles are suitable for roofs with a pitch of 4/12 or greater.

Low Sloped Roof Shingle Installation

For roofs that fall between the minimum and normal ranges, such as a 3/12 pitch, shingle installation is possible, but special precautions are necessary. In these cases, you must use either a double layer of asphalt-saturated felt paper or a single layer of ice and water shield beneath the shingles. It’s important to note that if your roof is only slightly above the minimum pitch, you may want to consider alternative materials instead of shingles.