How Much Drop Should A Rain Gutter Have

Calculate the gutter slope by dividing the length of the gutter needed by 10.

How much drop should a rain gutter have.

Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. 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. For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e. Gutters should slope an inch or two for every 40 feet.

That said gutters need to be completely level from front to back or water could spill over either edge. Size downspouts to fit the gutter. For rainy climates where gutters will handle a larger amount of water for long periods they should have a maximum distance of 18 inches apart between them. As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering.

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. This brings up another important rule to keep in mind. This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end. All guttering must slope toward the nearest downspout.

Place the line spirit level on the string. If you live in a warm place with sporadic rain you can hang gutter hangers close to the middle of the gutter with a spacing of no more than 36 inches or three feet apart from the center. For example for every 10 feet of gutter they need to drop 1 2 inch from the high end to the downspout. Doubling the number of downspouts halves the required capacity for each.

If the pitch is too gentle water will just fill up in the gutters until it overflows and a too sharp pitch isn t aesthetically pleasing. This allows the water to flow gently but. To ensure that gutters drain properly make certain they slope inch for every 10 feet toward a downspout. Gutters need to be pitched at a 5 degree angle.

For gutter runs longer than 40 feet it s best to pitch the gutter down from the middle to a downspout at each end.