How Many Downpipes Do I Need For My Roof

Roof area m gutter flow litres sec roof area m downpipe at centre half round 76mm 0 7 34 0 8 38 112mm 1 8 86 2 6 125 squareflo 3 2 154 3 8 182 125 68mm downpipe 3 8 182 4 6 221 82mm downpipe 4 0 191 4 9 235 regency 4 2 202 4 7 226 highflo 5 4 258 6 0 289 stormflo 110mm 11 1 534 12 4 598 160mm 12 5 601 14 0 673 downpipe at end half.

How many downpipes do i need for my roof. The average roll of 15 pound roofing felt covers about 400 ft 2 or 4 squares while the average roll of 30 pound roofing felt covers about 200 ft 2 or 2 squares. Downpipes should not serve more than 12 metres of gutter length for each downpipe. Also the various styles of guttering that are available have different flow rates. Build your roof empowers you to select each layer and component that goes into your total protection roofing system so that you get.

The program will calculate the size and number of downpipes downspouts leaders required and the eaves gutter sizes for any roof. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. Choosing a contractor contractor checklist financing your roof re roof 101. Frequency and positioning of outlets downpipes.

To calculate the average catchment per downpipe divide the roof catchment area by the number of downpipes. November 29 2019 the number of downpipes you need will depend on the size of your roof and your chosen style of guttering. Rolls of felt are 36 wide x 144 long for 15 and 72 long for 30. Calculate the number of outlets per run.

5 inch 5 520 square feet. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. If a roof s various drainage areas call for different size gutters go for the biggest one k style. You can choose a downpipe size and calculate the number required and the corresponding eaves gutter size.

It is the roof area the pitch of the roof and the number of drops downpipes coming down from outlets in the guttering around the building determine the flow we will need to know these to calculate the flow capacity for you. Size downspouts to fit the gutter. Storm damage how to spot a roof leak signs of roof damage signs that you need a new roof ice damming. Per downpipe 223 8 47 4 76m 2 five downpipes are required round up to the next whole number step 6.

Average catchment per downpipe roof catchment area. Always check the measurements of your building and work out exactly how much downpipe will be serving each gutter. Then use the information below to see what size gutter you need. Doubling the number of downspouts halves the required capacity for each.

Determine the average catchment area per downpipe. You do not want to put extra pressure on the system. The code limit is 150mm for dp s and 26 800 sq mm for flat eaves gutters. 6 inch 7 960 square feet.