Here Are 10 Possible Reasons Why Your Roof Is Leaking

Nick P. Cellucci
Written by Nick P. Cellucci
Reviewed by Ami Feller
Updated January 31, 2022
A house with lawn and garden
Photo: AnnMarie / Adobe Stock


  • Unaddressed roof leaks can cause water damage.

  • There are many common causes for a leaky roof.

  • Wear and tear from harsh weather often contributes to leaks.

  • Most roofing repairs are complex and should involve a pro.

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We rely on our home’s roofing to protect us from the elements. Even small water leaks can be frustrating, and if left unaddressed can lead to costly water damage that can harm your home.

Use this list of common roof leak causes to figure out how to locate your roof leak, and determine the sort of roof repairs you may need.

1. Broken or Blown-Off Shingles

One of the easiest problems to spot is shingle damage. The outermost layer of your roof and the first layer of protection against the elements, shingles can be broken off by high winds, heavy rains, or hail. If you notice different-colored patches on your roof or missing shingles littering your yard, your leak may be caused by shingle damage.

Whether you have asphalt shingles or roof tiles, you should be able to match them by color and manufacturer and have a local roofer install them properly. Swapping out broken shingles costs $250 to $600.

2. Cracked or Damaged Flashing

Flashing are thin pieces of metal installed under shingles, on roof joints, and around chimneys, dormers, or skylights. These pieces serve as a water-resistant barrier that may be either visible or concealed by a rubberized top coating. Wind and rain can erode flashing or the tar used to seal it together, causing cracks.

This type of roof damage can be difficult to spot, especially if your flashing is concealed. If you’re unable to locate the source of the leak or are unsure if damaged flashing is the cause, call a professional roofer to conduct a roof inspection and check around your joints. Flashing repairs run from $300 to $1,500.

3. Improperly Sealed Valleys

Valleys are areas where two planes of your roof meet at the bottom of a slope. "Rainwater inevitably runs through these valleys as it trickles down your roof,” says Ami Feller, Angi Expert Review Board member and owner of Roofer Chicks in New Braunfels, TX. “During a heavy rain, valleys can carry as much water as a creek would.” If your valleys are not properly sealed or the seals are damaged from erosion, water may seep into your home and cause water stains along the seams of your roof.

Repairs to these areas are complex and involve laying a new leak barrier and shingling. Call a roof repair company to help deal with this type of damage.

4. Disintegrated Roof Vent Booting

Roof vents are small pipes that stick out from your rooftop to release excess moisture from inside your home. They’re often sealed using a tight rubber boot, but this material tends to disintegrate over time. Leaks from these areas will manifest as dark spots with a musty smell. You can have your rubber boots replaced with longer-lasting lead boots for about $300 to $600.

5. Ice Dam Buildup

Roofline with serious ice damming
Photo: zerocattle / E+ / Getty Images

Ice can accumulate along the edge of your roof during colder winter temperatures, forming a dam that prevents melting snow and water from properly draining. This creates extra weight that sits on your roof for prolonged periods and causes damage.

You can deal with ice dams by using an ice melt product from a home improvement store. You can also prevent them from forming by investing in a roof rake. This long-handled tool helps you reach up and drag snow off the edge of your roof before it has a chance to melt and refreeze into ice.

6. Holes in Siding or Windows

Sometimes, what you think is a roof leak may actually be coming from holes in your siding or windows. Water can penetrate even the smallest gap, so caulk window areas and siding as you notice damage to save on repairs. Full replacement for damaged siding costs $225 to $375 per square foot.

7. Improperly Installed Skylights

Water stains or drips around the sides of your skylights are easy to spot and may be signs of improper fitting or that the insulation around their edges may have decayed. Clear debris from the skylight and look for cracks in the glass.

You can seal cracks with clear silicone, but if the leak is coming from around the sides of the skylight, you may need to have a roofing company repair the flashing or insulation around it.

8. Clogged Gutters

Gutters clogged with leaves
Photo: AlpamayoPhoto / iStock / Getty Images Plus / Getty Images

Gutters transport excess water away from your roof, so when they clog it can cause buildup and damage that leads to leaks. If you don’t see leaves sticking out of your gutter, you may still notice a lack of water coming from your downspout.

The easiest way to remove debris is to climb up and pull it from your gutters with your hands or use a leaf blower. We recommend gutter cleaning as part of your spring and fall outdoor maintenance routine.

9. A Cracked Chimney

Brick and mortar chimneys can erode due to harsh weather. You may notice holes where the chimney connects with your roof or loose flashing or shingles around it. A leak by your fireplace could also indicate a crack in your chimney cap, the metal cover used to keep rain and animals out.

Homeowners should consider hiring a chimney specialist to handle these repairs. Even if there is damage to your roof, materials used for chimneys are typically different from those for standard roofing fixes.

10. Condensation in Your Attic

If your attic shows signs of mold or mildew or has a strong, musty odor, water condensation is likely inside. Call a pro to treat existing mold growth, then prevent future problems by ensuring all roof vents are clear from the interior. You can even install a large ventilation fan in your attic to help circulate air and regulate its temperature.

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