1 4 Roof Slope

3 of rise per 12 of run is the same as 1 of rise per 4 of run or 1 4 25.

1 4 roof slope.

This means that the rise of the slope goes up or down 8 inches for every 12 inches. For most home styles roof pitches fall in a range 4 12 a moderate slope up to 8 12 fairly steep. If the rise is 6 inches for every 12 inches of run then the roof slope is 6 in 12 the slope can be expressed numerically as a ratio. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.

High pitched roofs often need extra fasteners and their pitch can be as high as 21 12. A 3 in 12 roof rises 3 for every 12 of run. That s the same as a 14 degree slope or a 25 slope. Liquid applied roofing must have a design roof slope of 1 4 12 or greater 2 slope.

Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle. The table below shows common roof pitches and the equivalent grade degrees and radians for each. A 4 12 is a roof slope that rises by 4 inches for every 12 inches across. They have a pitch ranging from 4 12 to 9 12.

The basic ranges of pitch are not uniformly defined but range from flat which are not perfectly flat but sloped to drain water up to 1 2 12 to 2 12 1 in 24 to 1 in 6. These roofs have a pitch less than 4 12. Conventional roofs are the easiest to construct and you can walk on them safely. This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit.

While roof slope is typically expressed in rise it can also be expressed in degrees or in percent of slope. Why is the roof slope 25. Low slope roofing which requires special materials and techniques to avoid leaks and ranges from 1 12 2 12 to 4 12 1 in 3. This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof.

Slope ratio a roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope. Most roof s have a pitch in the 4 12 to 9 12 range. To put it in perspective the angle of this slope would be around 30 degrees. Conventional from 4 12 1 in 3 to 9 12 3 in 4.

An example for a steep sloped roof is 8 12. You can also calculate roof pitch even without using a roof slope calculator.