Minimum Slope For Roof Drainage

How to use the calculator.

Minimum slope for roof drainage.

For metal panel roof systems with nonsoldered seams with applied lap sealant ibc 2018 prescribes a 1 2 12 minimum roof slope. 1 see sentence 9 26 3 1 2. 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. 3 profiled metal roof cladding systems specifically designed for low slope applications are.

Roof replacement or roof recover of existing low slope roof coverings shall not be required to meet the minimum design slope requirement of one quarter unit vertical in 12 units horizontal 2 percent slope in section 1507 for roofs that provide positive roof drainage. 2 see sentence 9 26 3 1 3. 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. Adding a roof can create drainage problems if the roof pitch is too shallow.

For standing seam metal roof panel systems a 1 4 12 minimum roof slope is prescribed. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches. Asphalt shingles continue to be the most widely installed roof covering option in north america.

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. Notes to table 9 26 3 1. For household sinks the drain pipe diameter is often either 1 5 or 2. This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction.

They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. Asphalt shingles minimum roof slope roof pitch r905 2 2. Drain pipe slope calculator. The following diagram lays out the different terms that are used in the calculator.

This means that the rise of the slope goes up or down 8 inches for every 12 inches. These considerations include the length of the roof the roofing material the size of the roof as well as the. Toilet waste lines are often 3 or 4. An example for a steep sloped roof is 8 12.

Asphalt shingles can only be installed on roof slopes of 2 12 or greater.