Rain Off A Roof

How to redirect rain off a roof 1.

Rain off a roof.

Designing a flat roof for runoff how water runs off a roof depends on the amount of rainfall and how quickly it needs to drain. Paint the drip edge. 1 of rain on 1 000 sf roof will yield 623 gallons. Score the surface of the drip edge with 80 grit sandpaper.

To find how much rain you can collect in an average rain year multiply this number by the average inches of rain. Multiply the area of your roof by the amount of rainfall you wish to calculate for. Oct 7 2018 explore joyce weber s board water runoff ideas on pinterest. Roof area ft2 x precipitation amount in x 0 623 amount collected gallons easy formula to remember.

Roof area m2 x precipitation amount mm amount collected liters. See more ideas about outdoor gardens backyard front yard. Block out distractions to. For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain.

Take the dimensions of the footprint of your roof and convert them to inches. For example if you have a roof that measures 1 500 square feet that equals 216 000 square inches. The number of feet multiplied by 144 equals inches. Rainwater collection calculation formulas and equations.

In this example 600 x 240 x 1 144 000 cubic inches of water divide by 231 to get the number of gallons because 1 gallon 231 cubic inches. If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. This is done to give the paint a better surface to adhere.

A common slope used that covers most materials is 2 12 which means that for every foot the roof steps up or down 2 inches. Turn it upside down so the. Place a piece of standard metal drip edge onto a table or between a pair of sawhorses. The drainage system of any roof can be located at the edge or in the middle of the roof.

If you get about 10 inches of rain over the course of the spring and summer an average 1 360 square foot roof would yield 8 160 gallons of rainwater.