Common Roof Leak Causes

Here are some typical reasons why your roof may be leaking.

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1. Your Roof Needs to be Replaced

Every roof has a limited lifespan. After many years, shingles can blow away and roof sealants and roof coatings can begin to break down and leak. If your roof is past its prime, visit the Lowe’s Roofing Installation page to have one installed by a trusted contractor.

Tip

See How to Install Roof Shingles for do-it-yourself help.

2. Your Roof Hasn’t Been Properly Maintained

Roofing requires some occasional upkeep such as cleaning your gutters, replacing missing shingles and removing heavy snow and ice buildup. Failing to perform regular maintenance can cause damage to your roof, which can lead to leaks.

3. Flashing May Be Cracked or Exposed

Roof flashing is sealed with tar or another type of sealant to keep water from penetrating the structure. Over time, seals can break down, resulting in a leak. Severe weather or strong winds can also cause the flashing to warp or crack.

4. Roof Valleys Aren’t Properly Sealed

A roof valley is a portion of a roof where two slopes connect. Pooling rainwater and accumulated ice can compromise the sealant in valleys over time.

5. Vent Booting Is Cracked

Roof boots are a special type of flashing used to seal around pipe vents that exit onto your roof. If this flashing is missing or damaged, it can allow water to seep down into your attic, creating wet spots in your ceilings or on walls.

6. Your Chimney is Damaged

Your chimney is built of masonry materials and mortar that can corrode and crack over time just like other roofing components, which is why it’s important to perform regular chimney inspections.

7. Your Skylights Are Damaged

Skylights that aren’t installed correctly or that were installed many years ago and may have leaky seals are another common source of roof leaks. This type of problem is usually easy to diagnose as you’ll simply notice water dripping into your home around skylights.

8. Your Gutters Are Clogged

Gutters perform an important function around your home, namely channeling water off your roof and away from your home’s foundation. However, if your gutters are clogged, this can cause water to pool on your rooftop and soak in over time.

9. You Have Damage from Weather or Ice Dams

Inclement weather such as storms and high winds can cause missing shingles and fragile tree limps to fall on your roof, leading to holes or warping of the roof’s structure. Also, as winter snow collects in roof joints and melts and refreezes over time, it can form what are known as ice dams. The extra weight created by the ice can weaken roofs, plus ice dams prevent melt water from rolling off roof shingles, causing it to back up under the shingles and creating the potential for leaks.

10. You Have Excess Dampness or Humidity in Your Attic

Even if rainwater isn’t penetrating your roof, moisture can accumulate in your attic due to condensation from extreme temperature differences and drip down into your ceilings. If this occurs, you may notice large, stained portions of your ceiling, moldy spots or a musty smell lingering in your home.

Caution

Mold in the home can be hazardous to your health. If you notice mold when repairing your roof or suspect that mold may be present, contact a professional to have your home tested and cleaned.

How to Fix Roof Leaks

A man on a roof using a nail gun to attach shingles.

Here are the steps for how to find a roof leak and address the issue.

Instructions

Inspect around ceilings and walls in your home to see if you notice any stains, discolored spots or visible drips. Next, enter your attic with a flashlight to see if you can easily see the source of the roof leak. If you can’t, grab a garden hose and enlist a couple of helpers.

Use a tall ladder to safely go up on your roof and spray water over the area you suspect may be leaking while one of your helpers watches for leaks in the attic. Have your other helper nearby to steady the ladder and assist with the garden hose. This technique will give you a general idea of what area(s) of the roof you’ll need to focus on. Follow the remaining steps for additional tips and solutions.

Tip

If you’re in the market for a new ladder for do-it-yourself tasks, check out our Types of Ladders Buying Guide to discover what your options are as well as some tips for safely using a ladder.

A closeup of a white dormer window on a roof.

Dormer windows add beauty to any home, but their complex structure provides many surfaces and joints where water can enter. To prevent this, check around any places where the caulking may have deteriorated, or the flashing may be compromised. Skylights are another area prone to leaks. Look for wet spots on your ceiling around skylights to identify areas that may need resealing, repairing or replacing. See How to Repair a Leaky Skylight for more help.

Tip

Many white roof sealants create watertight joints around dormer window and roofing joints while reflecting more of the sun’s rays than black-tined products, reducing heat damage and lengthening the lifespan of the product.

Falling tree branches due to inclement weather is a major cause of roof damage. While small cracks can be treated with a rubberized wet patch, holes and other serious damage will require the services of a professional. Once the issue has been mitigated, it’s important to guard against future damage. If you have trees close to your home, prune nearby branches —especially ones that are old and diseased — to prevent them from falling onto the roof in the future. If the entire tree is diseased or unstable, you’ll want to have it removed by a professional.

It’s important to keep your chimney in good working order both to prevent it from smoking up your house and to protect your home from fires. Regularly cleaning and inspecting your chimney, or hiring a professional to do the job, is paramount. Plus, a clean chimney is much easier to inspect for cracks and damage that could cause leaks in your home. For more information on proper chimney maintenance, including help on whether it’s best to complete the task yourself or hire pro help, see How to Clean a Chimney: DIY or Call a Professional?

How to Repair a Leaky Roof