If a roof s various drainage areas call for different size gutters go for the biggest one k style.
Calculate gutter size uk.
5 inch 5 520 square feet.
Calculate the area of a roof to work out how much guttering is required.
Now finally you can find the appropriate gutter size by looking at the following figures showing the relationship between different gutter systems and the roof area they ll be able to drain.
So for a roof that is 5 m long with a height of 4 m and the roof width is 8 m which makes the half roof width 4m we can calculate the effective roof area like this.
Calculate effective maximum roof area b c 2 x length of roof area in m installation.
Then use the information below to see what size gutter you need.
Total roof area also affects runoff.
Refer to bsen 12056 part 3.
An inch of rain is not much but it if falls in half an hour it could flood a gutter.
For example a 5 inch gutter system requires at least 2 x 3 downspouts and a 6 inch gutter system requires 3 x 4 downspouts.
Then use the chart below to see what size gutter you need.
For a typical gutter run up to a maximum of 10m the ratio of gutter lengths is calculated from.
Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage.
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.
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 ø downpipe appears suitable but check.
If a roof s various drainage areas call for different size gutters go for the biggest one k style.
These figures are based on a rainfall intensity of 75mm hr roof pitch not exceeding 50º gutters running full.
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.
Gather some basic weather information to calculate the proper size for gutters and downspouts for a house.
Refer to the gutter packaging or specification for the recommended downspout size.
Picking your gutter size.
Gutter ratio l1 l1 l2 where.
Match your downspouts to the gutter size you chose in step 7.
Depending on building type a safety factor should be allowed for the sizing of internal gutters.
That part of the gutter in which the angle obstructs the flow.
Choose gutter outlets according to published flow rate capacities.
5 inch 2 500 square feet.
5 inch 5 520 square feet.
For accurate project specific advice on rainwater flow calculations contact our friendly knowledgeable team on 0800 644 44 26.
6 inch 7 960 square feet.
Determine the size of your downspout.
5 inch 5 520 square feet.
Roof drainage layout and calculations.
