It’s a matter of gravity. In order for your gutters to function the way they should, rainwater needs to run “downhill” toward the downspouts. Gutter pitch is the angle the gutter system should be sloped to allow water to flow through the gutters and into the downpipes. When the gutter pitch is wrong, it can make your home’s exterior vulnerable to serious water damage.
Gutter Pitch Definition
When someone passes by your house and looks at the roof, the gutters will appear as a straight line. Hopefully, they are not! Gutter pitch, also known as gutter slope and gutter angle, is the degree gutters should slope to let water efficiently reach the downpipes. Gutter installation professionals advise, starting from the opposite corner of the location of a downspout, a ¼ inch pitch for every 10 feet of guttering.
Too Much Pitch
When the gutter slope is miscalculated and there is too much pitch, the sharp angle can result in the rainwater moving too quickly. Overflowing gutters send undirected water up into soffit and fascia, down siding, and into cracks in the foundation.
Too Little Pitch
If the water flow is sluggish or non-existent, it is most likely a sign of a gutter system with an improper gutter slope. Too little pitch and the water can’t move downward. When water collects in the gutter channel, it weighs the gutters down, putting stress on the fascia, eventually damaging both the gutters and fascia boards.
Incorrect gutter slope doesn’t effectively flush out leaves, dirt, twigs, needles, roofing shingle granules, seeds, pine cones, etc. When it accumulates in the gutter system and then combines with standing water, over time debris turns into sludge, adding more weight to the gutters.
When gutters are pitched incorrectly, it can create gaps where water will escape between the back of the gutter section and the fascia boards. This might cause water to run down one specific area of the house exterior, damaging siding or eroding brickwork. Often these gaps go undetected for long periods of time and if the problem is not fixed, can lead to expensive-to-repair structural issues.