Minimum Road Gutter Slope

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

Minimum road gutter slope.

This means that your gutter should be a half inch lower in height at every 10 foot mark until you reach the downspout. Typically on straight road sections the drainage gradient is at least 1 3 due to the normal cross slope of 1 3. It should be noted that while a 1v 4h slope is acceptable that a 1v 6h or flatter slope is preferred for both errant vehicle performance and slope maintainability. It is therefore preferable to provide an obstacle free area of 10 ft 3 0m beyond the toe of steep side slopes even when this area is outside the clear zone.

Most contractors tend to set the slop at one quarter inch per ten feet of guttering. The gutter slope also called the pitch is the amount the gutter tilts down to let rainwater flow out of it. So what s the ideal amount of slope for your gutters. If gutters slope too severely they don t hold water and water could splash over the sides in heavy rain.

From the table above a gutter with diameter 100 mm 4 inches can be used. One exception to the minimum 0 5 dg limit can be found in the norwegian road design manual where the minimum drainage gradient is 2 instead of 0 5. The standard slope for rain gutters is half of an inch for every 10 feet. 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.

For design bid build projects the peo shall perform a gutter flow analysis for each. Typical values of drainage gradient. The minimal slope needed for proper gutter drainage is 1 25 cm 1 4 inch for every 3 metres 10 feet of gutter. The amount of collected water increases until it spills over the sides of the gutter.

Or you can slope the gutters down from each end toward a single downspout placed in the middle of the run. For gutter runs longer than 40 feet it s best to pitch the gutter down from the middle to a downspout at each end. If gutters don t slope water gathers in them. The downspout can be 75 mm.

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 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. A roof with area 45 m 2 can be drained with a gutter with slope 1.