7 Unexpected Causes of Roof Leaks

Are you experiencing a leaky roof and asking yourself “why is my roof leaking?” Wondering what common causes of roof leaks are? There are so many potential reasons here in Hillsboro, OR!

Learn why roof leaks are bad for your home and what may be causing them.


Why does a leaky roof matter?

Leaky roofs matter because problems flow from the top of your home. If your home’s roof is not in shape, you can count on other issues to develop. The biggest issue of all of these? Water damage.

Since your roof is the primary defense against outside elements, it needs to be an impenetrable roof. Once a hole develops, they only get bigger. This allows more water into your home and more and more cascading damage.

So what’s the big deal with water damage? It not only ruins your property inside your home, but actually attacks the physical structure of your home, causing rot and necessitating a full remodel of any part of the house it encounters. Further, mold develops and creates hazardous air quality in your home.

And the problems don’t just stop with water. Once there’s a hole, critters can get in and wreak havoc by leaving droppings and nesting in your home. This creates air quality issues and lasting problems with your home’s structure and insulation.

All in all, leaky roofs spell trouble for your home. Keeping an eye out for leaks is concern #1 — but why do leaks develop?

We’ve listed some of the most common causes of roof leaks below.


Issues with a leaky roof and need it fixed NOW?

Call Fivecoat Roofing at (503) 502-2987 to help mitigate the issue and give your home the shield it needs to protect itself.



Probably one of the largest causes of roof leaks is they have simply reached the end of their life. As a roof ages, it does what it was born to do — protect your home from the elements. Even perfectly maintained roofs are going to take a beating by design.

Even if nothing catastrophic happens to your roof, you can bet that once a roof reaches the end of its life — 20-25 years — you’re going to start developing some leaks.



Another big cause of roof leaks is wildlife seeking shelter when the weather turns. When animals like mice, rats, racoons, or possums get an idea in their head to break through your roof, there is not much that will stop them.

An even bigger problem with wildlife is that once there’s a small hole, they’ll find that and use it as a starting point to develop an even larger entry. The best way to ensure this doesn’t happen is to make sure debris does not build up on your roof. Critters are attracted to fallen branches and leaves, and piled up debris will eventually lead to holes in your roof.



Fallen trees and tree branches are a big reason many Hillsboro homeowners experience leaky roofs. The culprit is generally a toxic mixture of unhealthy or dead trees and stormy weather. Healthy trees can also fall and damage your roof, but it’s a lot less likely to fall with a moderate storm.

The best way to prevent this from happening is to survey the trees on your property within striking distance of your home’s roof and make sure they are healthy. If they’re not, call an arborist and see what they can do to either revive, or take down the tree.


Clogged gutters

When gutters clog, water pools. Ask any roofing expert and they’ll tell you — standing water is bad news for your roof. While roofs are designed to be leak proof when water falls onto it and runs off, they’re not designed to hold pooled water for too long. This is not because they aren’t waterproof, but because the sheer weight of water will force damage to the structure of your roof and cause a leak.

Gutters become clogged by debris getting jammed in the natural flow of your gutter system. This most commonly happens in autumn when the leaves are falling. During this time of year, make sure your gutters are draining as they should. You should be checking throughout the rest of the year as well — and even having them inspected, cleaned, and cleared regularly.


Not designed correctly for your roof slope

As we mentioned above, slope is crucial to the design of your roof. It’s what drains water efficiently and what causes your roof to operate correctly. While low-pitched roofs can still be just as leak-proof as steeply pitched roofs, they do need additional underlay material to ensure proper function.

If you work with unqualified roofing contractors, even new roofs can leak if your roof is low-pitched and not properly underlaid.


Poor venting

Improper venting with your roofs can cause leaks 2 different ways — through excess condensation in your attic and through leaks in the vents themselves.

If there are not enough vents, moisture building up in your attic will cause mold and mildew growth since it will have nowhere to go but to stay in the attic. This lessens the integrity of your roof and will eventually cause leaks in addition to the already existing water damage from the condensation build up.

Conversely, if vents are not properly sealed, they’ll eventually lead to leaks around the gaskets around the vent pipes. This could be a crack, gap, or missing nail, or just one that has worn out through years of use.


Faulty flashing

Flashing is the most important part of a roof, but most people know nothing about it. Flashings are found underneath shingles and around the joints of your roof (such as where a skylight or chimney joins a roof). This is what truly makes your roof waterproof, as it creates a watertight barrier in the pressure points your roof needs it most.

When the seal on the flashing breaks down or is installed improperly, water will seep through and cause leaking. Since these are in critical parts of your roof, when there is a flashing issue it should be fixed as soon as possible.


No matter the cause of your leaky roof, don’t wait to fix it!

A roof that leaks is not a roof at all. Once you ask yourself “why is my roof leaking?” it’s time to call the professionals at Fivecoat Roofing to get things sorted and your home back on track. Whether it needs a simple fix or a whole new roof, our expert and honest roofing professionals will get your roof back on track, no matter the cause of your roof leak.

Contact us today. Don’t wait!