How Many Downpipes Per Square Metre Of Roof

Size downspouts to fit the gutter.

How many downpipes per square metre of roof.

For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches. 1 roofing square 9 290304 m 3. 50 000 4 400 11 36. Per downpipe 223 8 47 4 76m 2 five downpipes are required round up to the next whole number step 6.

Roof pitch is a determining factor for cost of the roof as well as the roof area and the type of materials used. For slopes greator than 12 5 deg ncc vol2 suggests the min sheet width is 400mm. Or 12 drains required. To calculate the average catchment per downpipe divide the roof catchment area by the number of downpipes.

Areas a and b require 74 mm diameter downpipes and area c requires a 63 mm diameter downpipe see figure 2. 1 m 1 m. How many downpipes do you need. Using an international foot of exactly 0 3048 meters length.

74 mm diameter downpipes serve roof plans up to 50 m. Take the roof s total square footage and divide by the total square footage handled by one drain. Average catchment per downpipe roof catchment area. Any less than this the ncc vol2 suggests to design as a box gutter.

The number of downpipes you need will depend on the size of your roof and your chosen style of guttering. Doubling the number of downspouts halves the required capacity for each. A house in chicago has a roof whose actual drainage area is 1 000 square feet. The roof slope as per the code should be 12 5 deg.

Rectangular or circular downpipes. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. The result is the number of drains needed. Outside of the u s a degree angle is typically used.

Area made by a square having one meter per side. Requires flow to be calculated in one of the other calculators. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. 100 square feet 1 roofing square 9 290304 cubic meters si unit.

Rectangular or circular spitters any number of circular spitters and reduction in down pipe size by using a funnel section. This is because larger roofs require bigger volumes of water to be diverted away from them during periods of rainfall. The 6 in 12 pitch factor 1 1 multiplied by 1 000 yields an effective area of 1 100 square feet. Multiplying that number by the local maximum rainfall intensity 6 8 inches per hour yields an adjusted square footage of 7 480 square feet.