Minimum width 300 mm for commercial construction and 200 mm for domestic construction.
Box gutter fall ratio.
I fall or slope box gutters to be installed with a minimum uniform fall of 1 in 200 towards the outlet.
Calculate the gutter slope by dividing the length of the gutter needed by 10.
The standard is about inch per 10 feet.
This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end.
Box gutters allowable width slope and length.
Rainhead overflow or specific box gutter overflow must be at least 30mm below the height of the back of the box gutter.
Next place a ladder at the left side of the house and measure from the roof down to the gutter.
Increasing the pitch increases a gutter s handling capacity but the gutter may look askew over a long run.
Measure the length of gutter needed.
Multiply the number of feet by 1 16 inch to determine the total slope the gutter requires.
The minimal slope needed for proper gutter drainage is 1 25 cm 1 4 inch for every 3 metres 10 feet of gutter.
For example if the gutter is 16 feet long the end near the down spout must be 1 inch lower than the starting end.
As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering.
There is always some confusion as to how the slope affects the overall depth.