Drip Edge and Gutter Leaks: Why Water Gets Behind Gutters
Everything Gutter president Jimmy DeHart Sr breaks down exactly why water leaks behind gutters, the difference between fascia leaks and soffit leaks, and the simple fixes that solve both problems.
Water leaking behind a gutter is one of the most common gutter complaints Jimmy DeHart hears from homeowners, and the root cause is almost always the same thing. The drip edge is not doing its job, or there is not one at all. Jimmy DeHart simplifies the problem to its essence. The drip edge is a metal flashing strip installed along the roof edge, extending slightly over the back lip of the gutter. It does one thing: it catches water as it runs off the shingle edge and directs it forward into the gutter trough. Without a drip edge, water running off the roof can curl back along the underside of the shingle edge and travel behind the gutter, where it runs down the fascia board instead of being carried to the downspout.
The physics are simpler than most homeowners assume. Water does not fall straight off the edge of a roof like a waterfall. Even on a steep roof, surface tension causes a portion of the water to cling to the shingle surface and wrap around the edge. The shallower the roof pitch, the more pronounced this effect becomes. A drip edge breaks that surface tension by providing a clean metal edge that the water cannot cling to, forcing it to drop into the gutter.
When Water Goes Behind the Drip Edge: A Different Problem
Jimmy DeHart draws a critical distinction between two problems that look similar from the homeowner's perspective but have completely different causes and fixes. Water leaking behind the gutter, running down the outside of the fascia, is a drip edge issue. Water showing up in the soffit, dripping from the underside of the eave overhang, is a different problem altogether.
Water in the soffit happens when the gutter is installed too high on the fascia board. When the back lip of the gutter sits too high relative to the roof edge, it lifts the shingle slightly. Instead of the shingle pointing on a downward slope toward the gutter, it gets propped up. Water running down the roof hits the lifted shingle, pools in the slight depression created by the lift, and works its way under the shingle and behind the drip edge. From there, it travels into the soffit and eventually drips out, often staining the soffit material and sometimes causing rot.
This problem can also be caused by gutter guards. Some gutter guard products are designed to slide under the first course of shingles, and if the guard is too thick or installed without adjusting the gutter height, it lifts the shingle edge just enough to create the same back-flow problem. Jimmy DeHart has seen cases where a perfectly functional gutter system developed soffit leaks immediately after gutter guards were installed because the guard changed the angle of the shingle at the roof edge. The fix for water in the soffit is resetting the gutter at the correct height so the shingle maintains its downward slope all the way to the drip edge.
What If the Drip Edge Is There But Water Still Leaks Behind?
Jimmy DeHart describes a scenario where a house had the correct drip edge installed, the roof angle was right, and water was still getting behind the gutter. The problem was that the drip edge was not bent out far enough. The metal was installed flush against the fascia so that the drip edge itself was tucked behind the back lip of the gutter rather than extending over it. A drip edge has to project outward enough that water falling from its lip clears the back edge of the gutter. The fix was simply bending the drip edge outward so it extended over the gutter's back lip by a quarter to half an inch.
This is the kind of problem that is invisible from the ground and requires getting on a ladder to inspect. A homeowner might reasonably assume that because they have a drip edge, it must be working. But the installation details determine whether it actually functions.
The Fastest Fix When There Is No Drip Edge
If the house has no drip edge at all, which is more common on older homes than most people realize, Jimmy DeHart offers two options. The proper fix is to have drip edge installed, which involves lifting the first course of shingles and sliding the metal flashing underneath so it extends over the gutter. The fast inexpensive fix is to run a bead of gutter sealant along the back edge of the gutter where it meets the fascia. The sealant creates a waterproof barrier that performs the same basic function as a drip edge. It will not last as long as properly installed metal drip edge, but it will stop the leaking immediately and can be reapplied as needed.
The sealant approach only works for water going behind the gutter, between the back of the gutter and the fascia. If water is going behind the drip edge and into the soffit, sealant at the gutter line will not help. The gutter needs to be repositioned.
For more on gutter maintenance, the gutter hanger types guide covers proper attachment methods. The plastic vs vinyl gutter systems guide compares material options. Homeowners in the West Grove, Pennsylvania area can reach Everything Gutter at everythinggutter.com. In all other areas click here for Gutter Materials and Installation or Call: (725) 278-6174
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