Roof Drain Pipe Slope

The roof pitch or slope factors for roof pitch are used to multiply or increase the rainfall rate if we are draining a sloped roof the roof drain or gutter or drain piping or downspout leader size diameter other size constraints e g.

Roof drain pipe slope.

Ss525 2006 code of practice for drainage of roofs. Cleanouts in draining systems cleanouts provides access to the sewer for rodding. But there are other issues concerning pitch to keep in mind. In general plumbing codes require pipes less than 3 inches in diameter to slope a 1 4 inch per foot of run.

Same logic with 1 8 slope 1 16 slope etc. It is generally accepted that 1 4 per foot of pipe run is the minimum for proper pitch on a sewer line. Smaller pipes are more likely to experience blockages than larger pipes and therefore require a steeper slope. An accurate calculation is essential for properly functioning plumbing.

Note that i said the drain pipe must be sloped rather than the french drain. 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. Slope of drain and waste pipes drainpipe sloping requirements vary according to the pipe s diameter. According to the chart for 1 8 slope per 12 of pipe for 5 000 square feet of roof area with a 6 per hour of rainfall the required pipe size is 8.

Sanitary drainage systems the purpose of a sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment. Pipes must slope slightly downhill to drain properly. Usually 1 8 per foot is plenty for drainage this is the same as the commonly recommended 1 slope. Drain waste and vent pipe hanger spacing support of drain waste and vent dwv pipes.

The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain. All of your drain pipe with one exception must slope slightly downhill. Tips on calculating drain pipe slopes use the longest level possible for your application for the best accuracy when the bubble on a level is about 1 4 of the way past the line it is about a 1 4 slope. 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.

Laying drainage pipes is a job for professionals but diyers can try their hand at less extensive drainage systems. The standard slope is anywhere from inch to 3 inches per foot. The flat roof must have sufficient slope to allow water to flow towards the roof outlets.