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10 Common Reasons for Roof Leaks

A leaking roof can cause significant damage if it is not corrected promptly. Because of the slope of a roof, it can be difficult to pinpoint the exact location of a roof leak. Gwen Co provides FREE Roof Inspections to all of our clients. So if you do have a leaky roof, you can rest easy knowing that we diagnose the leak and provide you an accurate estimate on the cost of repair. We run hundreds of roofing inspections a year, but below are 10 of the most common issues we see that cause leaky roofs.

1. AGE

Over time, roofing materials deteriorate on the roof and become prone to failure. As asphalt shingles age, they become worn, brittle and more vulnerable to damage.Thus resulting in water intrusion. Drastic changes in temperatures outside, and harsh weather conditions can cause your roof to become brittle and crack over time.


Any penetration through your roof should have a sealed flashing to prevent water intrusion. The most common cause of a leak is at or near a roof penetration. This is most commonly caused by a flashing failure. Inspect the rubber gaskets around the plumbing vents for cracks, animal damage or failure; this is a common culprit. Most of these can be temporarily sealed with caulk to prevent further damage until a repair is made.


If you have a roof with a low pitch to it, the risk for leaks increases. The slope of the roof plays a major role in the shedding of rainwater. Lower slope or shallow roofs tend to hold water just long enough for it to find any tiny imperfection or pinhole to penetrate. Asphalt Shingles are designed to shed water off a roof and are not recommended by the manufacture to be installed on low slope roofs less than 2/12. Special installation must be strictly followed when installing on slopes between 2/12 and 4/12.


Many times when I inspect the roof, it's covered in debris from trees. Leaves, branches, twigs, and those little helicoptery things that shed in the spring coat the roof, making it harder to inspect. Debris left on the roof surface will trap moisture against the roof, decreasing the roof's water shedding capability. Trapping moisture against the shingle will also cause it to fail prematurely. Trim overhead branches away from your roof (at least 6 feet). This will help keep the debris away.


Flashing on your roof is non-corrosive metal which seals transitions where water commonly travels. Common flashing points are where a roof meets a dormer, where the garage meets the second story, or a dormer wall, and around skylights. Flashings that fail or are improperly installed are a common cause of roof leaks.


Ridge Cap shingles are the shingles that cap the roof at the peak. Missing ridge cap shingles that have blown off during wind storms are a common cause of roof leaks.


Gutters stuffed full of debris from trees will cause them to backup under the edge of the roof system. This situation puts your home in danger of extensive damage; rotting wood, rotted rafter tails, rotted fascia board, and can lead to other damage. Keeping your gutters clean is critical.


You changed satellite providers recently and they removed the old satellite off of your roof and installed a new one. Question: What happened to the holes left behind from the old satellite dish? Satellite providers/installers are not roofing professionals, so don't assume or leave this up to them. The shingles with the holes in them need to be replaced so that you don't end up with a leak when their cheap caulk fails.


When you have an upper gutter that drains directly onto the lower roof, this can lead to the lower roof failure because it is continually over-saturated with H20. This is also a common cause of leaks. Also having the downspout of the upper gutter run down the side wall and terminate at the bottom corner is an invitation for a roof leak. The gutters should be extended all the way to the lower gutter run so that the roof isn't responsible for carrying the additional runoff.


Strong winds commonly rip off shingles exposing an area of your roof to the elements. This is dangerous because the rest of your roof becomes very vulnerable to blow offs. Anytime you have missing shingles, call Gwen Co to come out and repair it immediately. It's inexpensive to replace a few shingles if this happens, but prolonging or ignoring the problem also increases the cost of repair.

Roofer Gwen

Owner, Gwen Co, LLC

"Everything you love is under that roof."

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