Measure Rainfall On Roof

That s about 83 3 cubic feet of water per inch of rain for a 1 000 square foot roof.

Measure rainfall on roof.

For example if you have a roof that measures 50 square metres that equals 500 000 square cm 1 square metre 10 000 square cm. There are resources online how to calculate surface area of odd roofs. If you have a complex roof with many angles and levels i honestly couldn t tell you how to do that. The number of feet multiplied by 144 equals inches.

To calculate the runoff from any given rainfall. The main thing to realize is that 1 inch of rainfall is enough to create a 1 inch deep layer of water on your roof. The units of rainfall intensity are now quoted in litres per second per square metre l s m 2. Roofers have to know these equations to know how many square feet of shingles they d need to roof a home.

For example if you have a roof that measures 1 500 square feet that equals 216 000 square inches. The resulting figure represents the surface area of your roof in square metres. The british standard for the design of roof drainage is bs en 12056. The more intense the storm the higher the rainfall intensity will be.

To work out the surface area simply multiply the length in metres by width for square or rectangular roofs. Multiply the area of your roof by the amount of rainfall you wish to calculate for. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. Take the dimensions of the footprint of your roof and convert them to inches.

Up to the 2 inch mark it has rained 2 inches. All you have to do is take a straight sided can with a flat bottom like a cylinder make marks up its side every inch set it out in the open and wait for rain. This is equivalent to the old mm hour divided by 3 600. Part 3 that came into effect in 2000.

If you see that the can has filled with water up to the 1 inch mark then you know it has rained 1 inch. So the total volume of water on your roof is the square footage of your roof let s say it s 1 000 square feet times 1 inch 1 12 of a foot. Multiply this by the rainfall to get the volume of rain. Multiply the area of your roof by the amount of rainfall you wish to calculate for.