Minimum Roof Slope For Drainage

Use the longest level possible for your application for the best accuracy.

Minimum roof slope for drainage.

These considerations include the length of the roof the roofing material the size of the roof as well as the. 1 see sentence 9 26 3 1 2. In order to achieve this drop a slightly steeper angle of 1 40 1 44 should be the aim when installing a flat roof as this accounts for surface. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. An example for a steep sloped roof is 8 12. Adding a roof can create drainage problems if the roof pitch is too shallow. 2 asphalt and gravel or coal tar and gravel roofs may be constructed with lower slopes than required in sentence 1 when effective drainage is provided by roof drains located at the lowest points on the roofs.

For standing seam metal roof panel systems a 1 4 12 minimum roof slope is prescribed. 3 profiled metal roof cladding systems specifically designed for low slope applications are. The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches. Minimum roof pitch the minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.

Same logic with 1 8 slope 1 16 slope etc. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. Asphalt shingles can only be installed on roof slopes of 2 12 or greater. When the bubble on a level is about 1 4 of the way past the line it is about a 1 4 slope.

To put it in perspective the angle of this slope would be around 30 degrees. Asphalt shingles minimum roof slope roof pitch r905 2 2. 2 see sentence 9 26 3 1 3. This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction.

It can be argued that the minimum roof slope for drainage is 1 0 since this is sufficient to allow water to flow but there are other design considerations that must be taken into account when determining the final minimum slope. Normally 1 80 0 72 is the recommended minimum angle for a slope and this is universal across the vast majority of flat roofing systems regardless of the materials that they incorporate. Asphalt shingles continue to be the most widely installed roof covering option in north america. Tips on calculating drain pipe slopes.