1 8 Roof Slope

Access one of the rafters then take the measurement this way.

1 8 roof slope.

The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7. This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. Slope gradients are written as y x where y is a single unit in rise and x is the run. The calculator above can handle much of this math.

A roof pitch multiplier also known as a roof pitch factor is a number that when multiplied by the area covered by a sloped roof gives the actual area of the roof. The most precise way to find the roof s slope is by measuring it from the underside. Both numbers must use the same units. Measuring the slope from the rafters.

If the rise is 4 feet over a 24 foot span then the roof pitch was said to be 1 to 6 the pitch can be expressed numerically as a fraction. Either way let s see how you can calculate the slope of a roof without using a roof slope calculator. Angle the angle of a roof is the same as the roof s slope except instead of being. Coal tar built up roofs however can have a design roof slope of 1 8 12 1 percent but no less.

You can go by the measurements taken by walking the roof. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. The pitch of this roof is 4 8 12. This means that the rise of the slope goes up or down 8 inches for every 12 inches.

To put it in perspective the angle of this slope would be around 30 degrees. An example for a steep sloped roof is 8 12. Roof pitch calculator results explained. Set the level on the edge of the speed square as shown below then place the heel of the speed square on a rafter or gable edge of the roof.

Minimum roof slope roof pitch r905 9 1. A speed square and level can be used to easily find the pitch of a roof. This is read as a one in twelve slope. Built up roofs must have a design roof slope of 1 4 12 or greater 2 slope.

The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches. 1 pitch 1 01 2 pitch 1 02 3 pitch 1 03 4 pitch 1 05 5 pitch 1 085 6 pitch 1 12 7 pitch 1 16 8 pitch 1 21 9 pitch 1 25 10 pitch 1 31 11 pitch 1 36 12 pitch 1 42. The maths behind this number is that it is the square root of rise run 2 1. Since this is a flat roof or nearly flat roof.

For instance if you travel 3 inches vertically and 3 feet 36 inches horizontally the slope would be 3 36 or 1 12. 0 pitch 1 00x the roof area. Calculating a slope gradient.