You want at least a quarter inch of slope for every 10 feet.
Slope of roof guttering.
Working out gutter slope.
100 mm 4 gutter 75 mm 3 downspout.
This means that your gutter should be a half inch lower in height at every 10 foot mark until you reach the downspout.
Calculate the gutter slope by dividing the length of the gutter needed by 10.
Most contractors tend to set the slop at one quarter inch per ten feet of guttering.
2 grade 2 cm per 100 cm run 0 250 inch per 1 ft run.
1 grade 1 cm per 100 cm run 0 125 inch per 1 ft run.
This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end.
If the length of the gutter is 10 5 metres 35 feet the amount of slope required is 1 25 cm 1 4 inch multiplied by 1 metres 3 5 feet which when rounded up is 2 5 cm 1 inch.
Get on a ladder after a rainstorm and look in the gutter.
For spans longer than 40 feet it s wise to have a downspout on each end and start the high spot of the gutter in the center.
The standard slope for rain gutters is half of an inch for every 10 feet.
0 5 grade 0 5 cm per 100 cm run 0 0625 inch per 1 ft run.
Gutters need to be pitched toward the downspouts for the water to flow properly.
So if you have a 25 foot section of guttering you should set the downspout end of the gutter 5 8 of an inch lower 1 4 x 2 5 5 8 than the other end.
For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e.
If there s standing water it s not pitched properly.
As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering.
To correct this yourself you ll need to measure from the peak to the downspout.
The minimal slope needed for proper gutter drainage is 1 25 cm 1 4 inch for every 3 metres 10 feet of gutter.