Flat Roof Slope Requirements

Quick roofing guide to the international building code.

Flat roof slope requirements.

The steeper the roof slope the less potential for water to backup however the roofing materials established in chapter 9 must meet to minimum slope requirements. The profile is the shape taken by the sheets when you bend them to form panels. An example for a steep sloped roof is 8 12. Degrees to pitch rise in run table.

Proper roof slope can be an important consideration when designing high performance roof systems. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. All of these codes are produced by the international code council icc. There are two types of flat roof.

Iecc is of particular importance to low slope roof design due to its r value requirements which affect the amount of insulation that has to be included in roof assemblies. In general the minimum slope for a flat roof is 1 0 but as stated earlier this is only possible in theory. Asphalt shingles continue to be the most widely installed roof covering option in north america. Minimum slope for roofing materials.

Following is a review of code requirements and nrca s roof slope guidelines as well as some additional factors designers should consider. However you can only use this pitch with built up roofing or specialized synthetic roofing. This means that the rise of the slope goes up or down 8 inches for every 12 inches. The minimum slope of a roof depends on the roof s profile.

Roof pitch or roof slope. Roof slope equivalents as rise. Roof pitch multiplier table. The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches.

Run in degrees and as percentage the minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. To put it in perspective the angle of this slope would be around 30 degrees. First off lets get some terminology out of the way. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. Cold roofs and warm roofs. Complete list of roofing types. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay. Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling.