Roof Drain Pipe Slope

The standard slope is anywhere from inch to 3 inches per foot.

Roof drain pipe slope.

Smaller pipes are more likely to experience blockages than larger pipes and therefore require a steeper slope. Usually 1 8 per foot is plenty for drainage this is the same as the commonly recommended 1 slope. The flat roof must have sufficient slope to allow water to flow towards the roof outlets. But there are other issues concerning pitch to keep in mind.

Laying drainage pipes is a job for professionals but diyers can try their hand at less extensive drainage systems. Cleanouts in draining systems cleanouts provides access to the sewer for rodding. Larger lines such as 8 pipe actually require less pitch due to the larger circumference of the pipe. All of your drain pipe with one exception must slope slightly downhill.

Note that i said the drain pipe must be sloped rather than the french drain. Drain waste and vent pipe hanger spacing support of drain waste and vent dwv pipes. Pipes must slope slightly downhill to drain properly. The term slope is also frequently used and has the same meaning as pitch.

The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain. A slope of less than 1 4 inch per foot will cause constant drain clogs and a slope of more than three inches will allow the water to drain without the solids. Slope of drain and waste pipes drainpipe sloping requirements vary according to the pipe s diameter. Ss525 2006 code of practice for drainage of roofs.

Same logic with 1 8 slope 1 16 slope etc. In general plumbing codes require pipes less than 3 inches in diameter to slope a 1 4 inch per foot of run. Sanitary drainage systems the purpose of a sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment. According to plumbing code drain pipe has to be sloped a minimum of 1 4 inch per foot and a maximum of three inches per foot or vertical.

It is generally accepted that 1 4 per foot of pipe run is the minimum for proper pitch on a sewer line. An accurate calculation is essential for properly functioning plumbing. To size the vertical roof drain for the same parameters 5 000 square feet of room area and 6 per hour of rain consult table 1106 2 figure 3.