The asphalt shingle roof is the widely used roof covering in North America. This roof is resistant to extreme weather conditions and can add great value to your home. People choose this roof over other roofing options due to its easy installation and adaptability. Asphalt roofs are available in many colors and designs. Home designs not only include angled or steeper roofs but they may include a roof with a minimum slope.
What is the minimum slope requirement for an asphalt shingle roof?
Some manufacturers recommend 4:12, but the actual minimum is 2:12. The slope of the roof is measured in inches of vertical rise of the roof divided by the horizontal run of the roof. In 2:12 slope, the roof rises 2 inches for every 12 inches of horizontal run.
What is the “roof slope”?
The rise-over-run ratio is called the roof slope. If a roof slope rise is 4 inches when measured 12 inches along the bottom of the horizontal run, the roof slope is said to be 4:12. You can measure the roof slope either using tape or smartphone applications. The asphalt shingle roof contractors provide pitch estimator cards to measure the roof slope. A user-friendly roof slope estimator can help you measure the roof slope accurately for shingles.
What is the best slope for a roof?
For most home designs, the roof slope can be between 4:12 and 8:12. The best slope for a roof varies according to the type and purpose of the roof.
What is the minimum slope requirement where shingles can be installed?
The minimum slope for an asphalt shingle roof is 2:12. The roof pitch between 2:12 and 4:12 is considered as a low pitch roof, so shingles can be installed in the roof slope between 2:12 and 4:12.
Why is 2:12 the minimum?
Considering the roof slope requirement is important. For example, if it is a very low slope, water including snowmelt or rainwater drains slowly, and this increases the chances of lateral water movement around the shingles. Roof manufacturers recommend the roof slope between 2:12 and 4:12, as this is the lowest slope requirement for standard shingle installation. Shingle roofing is not watertight, and the minimum slope roof can work its way up between the laps. This is the reason why 2:12 is the minimum.
If you are considering asphalt shingle roofing or re-roofing, contact us!