Standard Flat Roof Slope

Pitch is thus the ratio of the rise in inches to a 12 inch run and is often expressed using a semicolon for example 6 12.

Standard flat roof slope.

Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot. It takes the manufacturer s recommendations the unique conditions of the roof as well as the skills and the expertise of the installer to arrive at the right slope. Generally these roofs have a pitch from 1 2 12 to 2 12 from 4 2 to 16 7. In general the minimum slope for a flat roof is 1 0 but as stated earlier this is only possible in theory.

If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks. The typical roof slope follows specific materials and design techniques to ensure perfect safety from leakage. Flat roofs are not perfectly flat in reality they need a small slope for water runoff. Flat roof slope minimum according to the international building code the typical built up flat roof that uses tar or asphalt goes by the guideline that for every foot 12 inches of a flat roof a minimum of inch must step up or down.

Low pitched roofs are generally difficult to maintain and you need special materials to prevent leaks. The roofslope auxiliary sloping compound provides a quick and easy way to fill in low spots on flat roofs and achieve positive slope to aid in proper drainage. This is the basis for calculating the angle which is approximately a 1 19 degree slope. Low slope roofs are from 0 to 3 12 in pitch.

This patented technology provides a durable finish with the ability to match existing roofing compositions. These roofs have a pitch less than 4 12. The most commonly used roof pitches fall in a range between 4 12 and 9 12. Generally these roofs have a pitch from 1 2 12 to 2 12 from 4 2 to 16 7.

This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs. Pitches above 9 12 are very highly angled and are designated steep slope roofs. See low slope roofing.

A a roof with a 6 rise for every 12 run has a 6 per foot or 6 in 12 pitch. Flat roofs which aren t perfectly flat require a small slope to allow for water runoff. A common range is given from 1 12 to 4 12 whereas conventional dimensions vary from 4 12 to 9 12 but the steep roofing technique follows slope above 9 12 with additional fasteners. Some sources consider low slope to include 3 12 pitch roofs.