How Much Slope On An 18 Ft Roof

Determine the minimum slope of the roof based on the roofing material.

How much slope on an 18 ft roof.

The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run. Thus a moderate 6 in 12 roof pitch means the roof rises 6 inches for every 12 horizontal inches it runs. In these instances a system of drains or gutters is necessary to channel the water away from the roof. The roof pitch is important in determining the appropriate installation method and how much roofing material will be needed.

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. How do you calculate the slope of a roof. A roof s pitch is determined by how much it rises for every foot it runs. Commercial buildings with a slope like this are considered low slope.

A square of shingles is the number of shingles needed to cover 100 sq feet of roof area. A roof slope of 7 12 is also good and can provide the additional benefit of helping minimize the effects of wind driven rain. This means that for every foot of the roof it must slope downward by at least one quarter inch. As a rule of thumb there are 3 bundles to a square assuming that you are using three tab strip shingles.

There are also 29 standard sized shingles. Outside of the u s a degree angle is typically used. The rise is the distance from the top of a stud wall to the peak of the roof. But the most commonly used pitches range between 4 12 and 9 12.

A 12 in 12 pitch is a steep 45 degree angle roof. When referring to roofs the term pitch means two. It is often compared to slope but is not exactly the same. Drains are usually located at the low points or valleys of the roof.

In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches. For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches. However from the wind uplift mitigation perspective a 7 12 roof slope can be considered as a two story building due to the higher overall steepness and profile of the roof. As aforementioned there is no standard pitch of a roof.

A 4 12 pitch being 4 inches of vertical rise over one foot or 12 inches of horizontal run. However shingles are packaged in a way that they are light enough for the average person to carry around. In roofing it is expressed in inches of vertical rise over inches of horizontal run. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.

There are advantages and disadvantages to having a steep pitch versus a shallow or low pitch the most obvious of which is the roof s ability to shed or withstand. You write the pitch assuming a run of 12 inches thus the ratio would describe how much a roof rises for each foot of the run.