If you ve got a simple gable end roof then it s easy you only need to know two figures one for either slope.
Calculating gutter sizes uk.
Increasing the capacity of your gutter system.
Add a fall to the gutters which we recommend you do anyway.
Design area effective area 5 x 10 x 1 29 64 5m run off 64 5m x 0 022 l s per m 1 42 l s from chart 125 x 100 gutter with 76 ΓΈ downpipe appears suitable but check.
The most logical way to choose your gutter size would be according to the area of your roof.
For example if your roof is 40 feet long and 20 feet wide you area will be 800 square feet.
6 inch 7 960 square feet.
Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage.
If a roof s various drainage areas call for different size gutters go for the biggest one k style.
5 inch 5 520 square feet.
Determine the surface area of your roof.
Calculate the square footage by getting up there with a tape measure.
Move the outlet downpipe from the end of the gutter to the middle.
Gutter ratio l1 l1 l2 where.
Change the style of gutters to one with a greater capacity.
L1 l2 selecting gutter size there is no standard rate of rainfall in the uk so for accurate calculations refer to an approved weather authority to get a site specific rainfall level.
As a consequence sizing the gutter spout is key to properly sizing a gutter system.
Lg 10 133 therefore reduction factor 0 86 d 0 1 gutter capacity x reduction factor 2 84 x 0 86 2 44 l s therefore the proposed system is suitable.