Flat Roof Slope Requirements

Proper roof slope can be an important consideration when designing high performance roof systems.

Flat roof slope requirements.

You need to consider the slope requirements of each panel to determine this minimum slope. In general the minimum slope for a flat roof is 1 0 but as stated earlier this is only possible in theory. First off lets get some terminology out of the way. Cold roofs and warm roofs.

Roof pitch multiplier table. Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling. To put it in perspective the angle of this slope would be around 30 degrees. Asphalt shingles continue to be the most widely installed roof covering option in north america.

Roof pitch or roof slope. 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. Express the slope of a metal roof by a ratio which indicates the pitch of the roof.

Degrees to pitch rise in run table. 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. Minimum and maximum roof slope limits vary based on specific roof system and project types. In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay.

Roof slope equivalents as rise. All of these codes are produced by the international code council icc. Since they vary in quality as well as method of installation the choice preferred for a flat roof will ultimately have an effect on the final slope of the flat roof. Complete list of roofing types.

The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. However you can only use this pitch with built up roofing or specialized synthetic roofing. Minimum slope for roofing materials. This means that the rise of the slope goes up or down 8 inches for every 12 inches.

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. There are two types of flat roof. Following is a review of code requirements and nrca s roof slope guidelines as well as some additional factors designers should consider. 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.

The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.