Gutter can be run level for appearance but addition downspout will be necessary see section on proper gutter and downspout sizing.
Proper gutter slope.
When you look at a rain gutter system from the ground it looks like it was parallel to the roofline of the house but they are slightly inclined so rainwater can flow straight to the downspout without problems.
To ensure that gutters drain properly make certain they slope inch for every 10 feet toward a downspout.
But in reality they must be sloped ever so slightly so the runoff water can flow downhill to the downspouts.
Or you can slope the gutters down from each end toward a single downspout placed in the middle of the run.
The gutter slope also called the pitch is the amount the gutter tilts down to let rainwater flow out of it.
Slope calculation this is a critical aspect in any rain gutter installation.
Calculate the gutter slope by dividing the length of the gutter needed by 10.
If gutters slope too severely they don t hold water and water could splash over the sides in heavy rain.
There are two factors that go into determining gutter position on the eave the pitch of the gutter and the roof slope.
For example if the gutter is 16 feet long the end near the down spout must be 1 inch lower than the starting end.
One of the biggest challenges involved in gutter installation is establishing the proper slope of the guttering.
Measure the length of gutter needed.
If gutters don t slope water gathers in them.
From a distance gutters appear to parallel the roofline.
The right rain gutter slope is subtle enough that you won t notice it from the street but also steep enough so that it easily sheds water towards your downspout.
Proper rain gutter slope.
For water to drain towards your downspouts your rain gutters need to harness the power of gravity so that excess water flows downhill.
To get started measure the side of the house directly under the gutter to determine its length in feet.
Multiply the number of feet by 1 16 inch to determine the total slope the gutter requires.
Gutter should be pitched 1 16 or greater per foot for proper drainage.
For gutter runs longer than 40 feet it s best to pitch the gutter down from the middle to a downspout at each end.
For example for every 10 feet of gutter they need to drop 1 2 inch from the high end 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.