
A leaky roof is a serious structural issue, and even minor leaks can cause tens of thousands of dollars in damage. If you want to fix leaks before they wreak havoc on your home, you’ll need to be familiar with what causes these leaks and how to detect them early on.
In this article, we’ll cover the most common causes of leaky roofs and show you how to spot them early.
Reasons Why Your Roof Might Be Leaking

If you’re wondering why your roof is leaking, it’s likely due to one of the following causes:
Cracked Flashing
Flashing is thin metal pieces installed underneath your shingles as well as on your roof joints to create a water-resistant barrier. Sometimes flashing is exposed, and in other cases, it is concealed. Exposed flashing looks like long sheet metal strips, whereas concealed flashing is hidden by a rubberized coating. If your flashing is broken, it will have noticeable cracks.
Flashing is usually sealed together using tar, which is known to corrode. If the flashing is exposed, wind, rain and other harsh elements could cause cracking.
Broken Shingles
Broken shingles are one of the easiest problems to detect. As shingles form the outermost layer of your roof, you should be able to spot a problem looking up from the ground. If you see any patches on your roof that are a slightly different color, this could mean that one or more shingles are defective and making your roof vulnerable to leaks. You might also find some shingles falling to the ground after heavy rains and high winds.
Improperly Sealed Valleys
Valleys refer to the low area where two planes of your roof meet. As these two planes of the roof are almost always sloped, water flows down into them, and if the valley isn’t properly sealed, it will be vulnerable to water intrusion. You can spot this problem by looking for wet areas along your roof’s seams.
Many factors can cause breaks in these seams. The original sealing may have not been properly done, someone may have stepped on it, or excessive amounts of ice and rain may have eroded it over time.
Cracked Vent Booting
A roof vent is a small pipe jutting out of the top of the roof that allows excess moisture from inside the house to escape. Leaks that occur in this area tend to leave behind mustiness and dark spots.
A roof vent is normally sealed by putting flashing around its opening and then slipping in a rubber boot, known as a vent boot, on top of where the pipe comes out of your roof. This flashing may decay over time.
Ice Dam Damage
Ice dams are ridges of ice that form at the edges of roofs. While this may not seem like any cause for concern, this ridge of ice traps the water from melting snow, preventing it from draining off the roof. The weight of the ice dam can also damage your roof, and when combined with the weight of the accumulating water, it can do even more harm.
Ice dams tend to form when heat from the attic causes the snowfall on the roof to melt, which then runs down the roof and refreezes at the roof’s edge. As more snow melts and runs down the roof, it will collect at the ice dam.
Improperly Installed Skylights
It shouldn’t be too difficult to spot a leak around your skylights. If you’re consistently seeing damp spots around your skylight or setting out buckets out to catch drips around the edges of your skylight, the cause is pretty obvious. However, if you see a leak or wet spots by the top of your skylight, it could instead be a problem with the flashing.
Leaks around skylights are usually the result of one of two things: either the skylight was improperly fitted when it was installed or the insulation around the edges of the skylight has decayed. There could be cracks in the skylight as well.
Clogged Gutters
If your roof only leaks sometimes, it could be due to clogged gutters. Peering up at your roof from your lawn, you may notice leaves and other debris sticking out from your gutter, which is an obvious sign that they’re clogged. However, even if you can’t see any debris, they still might be clogged, which is why you should pay attention to your downspouts during a heavy rainstorm.
Your gutters are designed to help carry water away from your roof and away from the foundation of your house. When they get clogged, however, they can no longer perform this vital service. This results in rainwater pooling in certain places on the roof, which gives it a better opportunity to make its way into your house.
Cracked Chimney
The most obvious sign of a leaking chimney is wear and tear around the chimney’s mud cap or the mortared area at the chimney’s top, so make sure to keep an eye on these. You should also inspect the mortared joints, where the roof and chimney intersect, for holes and check the shingles and flashing surrounding the chimney for cracks. If you notice the leak in the fireplace, chances are that the source of your leak is the chimney cap.
While you may assume mortar is fairly impenetrable, it’s merely a mixture of sand, cement and water and can erode easily when weather conditions are harsh.
Condensation in the Attic
If you’ve noticed mildew or mold growth in your attic, this probably means that water has made its way in from the outside. A musty odor in the attic is another sign of water intrusion.
As your attic is the uppermost section of the house, it is a place where outdoor and indoor temperatures meet. When these two come together, especially during frigid winters and sweltering summers, this can lead to condensation and, soon after, moisture.
If you discover mold growth in your attic, the first thing you want to do it treat it. Next, try your best to isolate the attic so large temperature fluctuations no longer occur. You should also check all your roof vents to make sure they’re clear from the inside. Installing a ventilation fan in your attic can help reduce or eliminate moisture issues.
Damage From Foot Traffic
Although you can’t really pinpoint foot traffic as the cause of a roof leak, it’s important to minimize the amount of time you spend walking on your roof. Roofing materials, while designed to withstand harsh elements, are not designed to withstand regular walking on by humans. It’s not hard to step on a critical component or crack a seal that was already precarious.
We urge you to avoid walking on your roof unless absolutely necessary. If your frisbee gets stuck up there, leave it and buy another one. Even if you notice damage on your roof, we recommend hiring a professional to fix it, as they know where to step and how to avoid your roof’s most vulnerable areas.
How to Tell If Your Roof Is Leaking

Even the smallest of leaks can cause serious damage to your foundation, walls and home exterior. But how do you know if your roof is leaking? To detect a leak as early as possible, keep an eye out for the following signs:
Water Stains
Water stains appear on your ceiling and often look like a big puddle with a brown ring. However, other water stains are more difficult to see and may occur in dark corners. If you come across discolored areas on your ceiling or walls, look closer for moisture, mold and other unmistakable signs of leaks.
Intermittent Dripping
If you notice drips, moisture and water stains and then they go away, that doesn’t mean the leak has magically repaired itself. You should still have it checked. For instance, your roof may have an ice dam, which is caused by ice and melting snow freezing and thawing. The thawed water makes its way underneath your shingles, freezes and causes intermittent leaks. Remember this rule: if you notice moisture, investigate it — even if the moisture appears to disappear after a short time. If you have a chronic moisture issue, it may damage your house permanently.
Spots on Exterior Walls
Every now and then, look under the roofline of your house to see if you notice anything. If you see water spots, this means there may be an issue where the roof and walls come together. Water sports here can indicate issues with the flashing.
Moss on Exterior Walls
If your exterior wall is mossy or moldy, this could be because it’s in a shady spot, although it could also mean you have an issue with your gutters or downspouts. While these components are made of a different material than your roof surface, gutters and downspouts are key components of your roof, as they help water drain from your roof and away from your foundation. If one of them is leaking, there may also be erosion under the gutters and moisture on the exterior of your house, depending on the location of the leak. You can minimize the issue of icy or clogged gutters, however, by installing gutter covers and fixing gutters that sag.
Missing Shingles
This one may be obvious, but if you notice any missing shingles, this means your roof is more vulnerable to leaks. You should also look for any issues in areas between shingles and other fixtures like chimneys, as well as any roof debris that is coming down through your downspouts. If your roof is getting patchy, this will make it more susceptible to leaks over time. Even if you haven’t noticed any leaks in your home, there still could be slow leaks in your crawl space or attic. If you notice any damage to your roofing, ask a professional for an inspection, which will tell you more about the current condition of your roof and whether you have any leaks.
How We Can Help

Roof repairs — perhaps more than any type of house repair — are not generally something you want to do yourself. There are several reasons to call the professionals.
- Safety: While some of the issues we mentioned can be fixed from within your house — such as dehumidifying your attic — most of these issues can only be fixed by walking on top of your roof, which we strongly discourage. The consequences of falling from a roof are usually catastrophic and can be fatal. Even if you are being extremely cautious, you lack the safety training and equipment that professional roofers have.
- Quality work: When you go with a professional roofer, you can enjoy the peace of mind that the job will be performed correctly. Even if you have done some roof work in the past, if you’re not a professional roofer, you will not be up to date on the latest roofing techniques. Without professional training, it’s also difficult to know exactly how to fix the problem — for instance, you may think a leak can be repaired by replacing a single shingle when it actually requires removing an entire section of your roofing deck.
- Guarantee on the work: Professional roofers usually offer guarantees on the repair work they perform. This means that, if anything goes wrong while the roof is being repaired, you’ll be covered for the additional repairs down the road. If you attempt to do your own repairs, you won’t have any such guarantee. In fact, the majority of roofing materials include a clause stating that manufacturer warranties become void if they’re not installed professionally.
- No risk of further roof damage: Certain areas of a roof are more vulnerable than others. If you walk around on your own roof, not only will you be putting your own life in danger — you also risk further damaging the roof you’re trying to fix. Professional roofers know where to step so that it doesn’t compromise the integrity and strength of your roof.
Contact Us for a Free Estimate
At Scro’s Roofing, we have served families in Raleigh, North Carolina, since 1995. We are proud to be a GAF Master Elite® Company, so you can feel confident that our team is trained to repair and install many types of roofs. When hiring us for your roof repair, you can be sure to receive expertise, remarkable talent and superior customer experience. We firmly believe that, when repairing your roof, honesty and transparency are extremely important. Before doing any work on your roof, we promise we’ll go over all issues with you and help you prioritize repairs. And once we’re finished, we’ll also clearly explain the work that was performed and provide you with a thorough report. It is our objective to help you save money and prevent stress by prolonging the lifespan of your home’s most vital feature.
To obtain a free estimate, contact us online or call us at 919-551-5104.