Top 10 Causes for Roof Leaks & How to Fix Them

window with rain and house in background

Roof leaks of any size can cause significant damage to a home if not discovered and repaired quickly. The smallest drip can symbolize a huge investment of time and money. We’ve outlined a list of the most common causes of roof leaks.

Being able to correctly identify a roof leak will help you fix it, tell you why it happened, and hopefully, avoid the same problem in the future.

1. The Flashing Has Cracked

flashing around chimney on tile roof

Flashing are thin pieces of metal designed to create a water-resistant barrier. Flashing seals areas of transitional space on a roof, like where roofing material joins a dormer, around a chimney, and along the edges of skylights.

Flashing may crack or slide out of place due to missing nails or cracked caulk. Cracked or exposed flashing leaves your home vulnerable to water damage.

What to Do About It:

  • Remove the nails securing the old flashing and discard the cracked section.
  • Place the new flashing along the seam.
  • Secure the new flashing into place using roofing nails.
  • Use a coat of roofing sealant along the nail heads to form an airtight barrier.

2. Your Shingles Are Broken or Dislodged

missing shingles

High winds and heavy rains can damage and dislodge shingles from the roof.

Shingles may become cracked, or their granules may become displaced, leading to moisture penetration.

Look for patchiness on your roof, as the different colors may point to missing shingles.

What to Do About It:

  • Use a pry bar or similar device to slide underneath the nails that connect the damaged shingle to the one beneath it.
  • Lift until all the nails are removed, and pull out the damaged shingle.
  • Replace with a new shingle.
  • Secure the new shingle using four nails.

Keep reading about shingle roof repair practices:

3. The Roof Valleys Aren’t Sealed Properly

Roof valleys

A roof valley is a section of the roof where two planes come together. These areas are usually sloped, and if not sealed properly, rain will get inside as it runs down the roof.

The seal may come apart for a variety of reasons, including cracking from pressure, erosion from weather over time, etc.

What to Do About It:

Improperly sealed valleys are best left to the professionals. Valleys are complex and so are the steps for repairing them.

Find a roof repair contractor near you

4. Ice Dams Have Formed

ice dam pulling off gutter

Ice dams form when heat from the attic causes snow on the roof to melt and run towards the bottom of the roof.

The water refreezes once it reaches the edge of the roof, creating a ridge. As this process repeats itself, an ice dam forms.

Ice dams prevent water from draining off the roof, leaving the roof susceptible to damage.

Not only does the added weight of the ice put a serious strain on the roof and gutter system, but it also leaves your roof more at risk of water seeping in where it doesn't belong.

What to Do About It:

  • Make sure your attic is properly ventilated.
  • Use a roof rake to remove as much snow as possible from the roof’s edge.
  • If you notice a dam forming, treat it with an ice melt product.

5. The Roof Has Deteriorated Over Time

old roof deteriorating

As your roof ages, it becomes less effective at combating rain, wind, hail, and other detrimental elements.

High heat and severe winters may cause even the strongest roofing materials to crack or break over time.

Proper maintenance can combat these problems, but keep track of your roof’s age and always take it into account when searching for leaks or structural damage.

What to Do About It:

Regular maintenance is the best method for keeping your roof durable the older it gets. Attempt to inspect your roof once or twice a year.

  • Clear away debris.
  • Scrub any areas with mold or moss growing.
  • Clean out the gutters.

Note: Don’t go up on your roof too often. You may crack or damage areas by walking on it too frequently. 

6. Your Gutters Are Clogged

clogged gutters in the fall

Clogged gutters are one of the most common problems facing homeowners.

Leaves, sticks, and other debris create blockages that prevent water from traveling away from the roof.

When water has nowhere to go, it begins to pool in your gutters, giving it the opportunity to seep through the roofing material.

Fortunately, while it may be a common problem, it’s also easy to prevent. Inspecting your gutters just twice a year makes a significant impact in fighting this problem.

What to Do About It:

  • Use a ladder, some gloves, and a garden hose to clean out your gutters.
  • Place a tarp beneath you as you work.
  • Drop any debris as you go so you can easily wrap it up for disposal.
Cleaning your gutters is a messy job, but it ensures proper water runoff, prevents ice dams, and relieves the gutter system from the added weight.

Find a roof repair contractor near you

7. Your Attic Isn't Properly Ventilated

attic with sun light

If your attic isn’t properly ventilated, it can lead to some serious and costly structural problems.

Without adequate ventilation, excessive amounts of moisture contribute to mold growth, mildew, insulation damage, and underlayment deterioration.

Each of these factors damages the underside of your roof, which in turn creates more opportunities for leaks.

What to Do About It:

  • Do what you can to prevent rapidly fluctuating temperatures.
  • Treat mold growth as soon as you spot it.
  • Ensure your attic is ventilated properly.

If your attic is not ventilated properly, determine the best system for your home. A ventilation system will circulate cool, dry air into the attic, replacing damaging hot, humid air. 

Common roof ventilation options include roof turbines, ridge vents, and gable vents.

Learn more about attic ventilation solutions:

8. There's Too Much Roof Debris Present

moss growth on wood shingles

Fallen branches, leaves, and pine needles trap water against the side of the roof.

This prevents adequate water run off, creating opportunities for water to penetrate underneath roofing material.

What to Do About It:

  • Keep your roof free from debris.
  • Trim any overhanging branches.
  • Remove fallen tree limbs and leaves.

9. Your Skylights Were Poorly Installed

skylight embedded in wooden roof

Improperly installed skylights are one of the easier problems to identify when it comes to causes of roof leaks.

If you notice wet spots directly adjacent to skylights, or you need to place drip pockets below them, you’ve found the cause of your roof leak.

What to Do About It:

  • Clear off any debris and attempt to determine if the skylight is fitted correctly.
  • Check for cracks around the flashing and window itself.
  • Seal any minor cracks with a clear roofing sealant.
  • If you notice cracked flashing, remove it and replace the section with a new piece.
Often, the best course of action is calling the skylight installer to have it refitted. Hometown Roofing Contractors makes it easy to find a qualified contractor close to your home.

10. There Is Excessive Moisture

rain coming off metal roof

In geographic areas that experience high amounts of rainfall each year, roofs put up with quite a lot.

If your roof has higher and lower sections, check the drainage system from the upper roof.

Gutters that flow directly onto a lower roof can over saturate the material, causing roof leaks.

What to Do About It:

Extend the downspout to the gutter or all the way to the ground to prevent this problem. Do what you can to prevent excessive amounts of water from being directed to one particular spot on the roof.

Find a roof repair contractor near you