Roof Slope Gutter Clearance

Roof pitch roof pitch factor.

Roof slope gutter clearance.

The steeper a roof s pitch the more windblown rain it can collect. Start at the highest point with the back of the gutter as high as it will go up against the bottom of the slate or tile or galvanised iron roof. For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e. Weather bureau records the maximum rainfall that could possibly happen in a 5 minute period in inches per hour for various regions.

The angle of a roof on a house is referred to as the roof pitch. The general rule is to slope the gutters at 1 4 th inch per 10 feet of gutters. And for a 12 in 12 pitch 1 4 in. Water will blow in there and rot the timber facia.

Slope the gutter down form there towards the spout. The distance below the projected roof plane varies with pitch. If the slope is slanted too sharply the gutters can t function at full capacity. There is no building code citation that forbids a gutter from draining onto a lower roof.

So it s a matter of what the home inspector or contractor considers acceptable. For a steeper 7 in 12 pitch 1 2 in. Hold one end of the level against the roof level it and then measure the distance between the roof and the underside of the level at its midpoint which gives you a 12 inch run. Required clearance of gutter below extended roof line roof pitch clearance below extended roof line 0 in 12 2 in 12 1 3 in 12 5 in 12 6 in 12 8 in 12 9 in 12 or greater.

If the gutter slope isn t properly positioned it will pool in the system and spill over the sides. Generally a contractor that drains a gutter onto a lower roof will say that it is an industry standard whereas a contractor that rants against it will say that it s not best building practice. Not only do your gutters need sloped at a precise angle but the downspouts need specific direction as well. You can measure pitch with a 2 foot level and a tape measure.

It s usually expressed as a number that looks like a fraction such as 1 12 for a very shallow roof or 18 12 for one that s very steep. For a gently sloped 5 in 12 pitch place the front lip of the gutter 3 4 in. This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end. If the run is long you may need flashing to cover the exposed part of the facia.

As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering. Roof pitch is very important for right roof gutter sizing. The numbers indicate the rise of the roof over it s run. Below the projected roof plane.