Skip to main content

«  View All Posts

Roof Leaks

Why Does My Roof Only Leak Sometimes?

November , 2023 | 13 min. read

By David Toth

roofer checking the flashing on a wall that has been leaking
Picture this: It's Friday morning, it's been a great week, and the weather has been perfect. Every day, you've been able to enjoy your morning coffee on your lanai and soak up the sunshine. You can see storm clouds starting to form in the distance, but you think nothing of it. After a long day at work, you drive home in the pouring rain only to have the realization that your roof is probably leaking. Again. Lo and behold, you return home to find water flowing in through cracks in the ceiling in the living room, and your furniture and belongings are soaked. After a stressful few days of flood cleanup and temporary roof repairs, it's suddenly Monday again, and it's sunny. You're busy at work, so you put off your roof leak repair yet again and forget about it until the next rainstorm. Do you see the trend here?

Listen, we get it. When your roof only leaks sometimes, it's easy to forget about repairing it on the days it's not causing problems. Or, maybe a roof repair is simply not in your budget right. Or maybe,  you just don't want roofing contractors in your home. We get it! RoofCrafters has been helping out homeowners like you for nearly 30 years, and we believe that these are all valid reasons.

homeowner sitting inside getting rained on from a roof leak

However, we also believe that a stable roof that provides you, your family, and your belongings optimal shelter and safety is equally important. If you're wondering why your roof is only leaking sometimes, and you're looking for professional help, we've got you covered. In this article, you'll learn about the different components that cause intermittent roof leaks, and how these problems can get fixed. 

Unraveling the Mystery: Intermittent Roof Leaks Explained


Inconsistent roof leaks generally occur during severe weather conditions. While your roof might be waterproof against regular rain, roof damage or installation errors oftentimes can affect its ability to keep water out from certain roof areas.

man drinking coffee inside with an umbrella, pots and pans catching roof leaks

These leaks might be visible several days into a heavy storm or never happen under similar conditions. You should always look out for water entering your home during heavy rain so that you know what's happening. There are a few different instances when you might experience a roof leak, such as:

Decoding Leaks: The Impact of Horizontal Rain on Your Roof


During rain and strong winds, you might have experienced rain that flies parallel to the ground. Since asphalt shingles are only designed to repel water falling perpendicularly, horizontal rain or wind-driven rain can seep between the shingles and or make its way behind the roof-to-wall or roof-to-chimney flashing.

a dormer on a shingle roof with loose flashing

This water will eventually seep through, even well after it has stopped raining. The reason that this happens is that the water takes much longer to travel under the roofing material through your attic, then through your insulation, and finally hitting the sheetrock where you are able to see the water damage.

Unveiling the Impact of Heavy Rain on Roof Leaks


Unveiling the Impact of Heavy Rain on Roof Leaks

You might have experienced a roof leak at times of heavy rain if you haven’t conducted proper maintenance. Having leaves and debris build up in your valleys or around chimneys, skylights or any other penetrations can create water dams, allowing water to back up in heavy rains. If your gutters are clogged and can’t drain the water fast enough, water can also back up on the roof and cause it to leak there as well.

debris on a flat and shingle roof


You should consider having your roof inspected by a contractor before the rainy season to clean up any leaves, tree debris, and clogged gutters. At that time, they'll also inspect for any damage that might cause the roof to leak in the near future. That way, you can potentially prevent any roof leaks that may occur.

Ridge Vents Cause leaks


If you have ridge vents, they may leak during heavy rain combined with strong winds. While they are designed to prevent water from entering your house, some types are less water-resistant than others. Ensure that you research the types of vents and the waterproofing that suits your needs to prevent any damage to your home.

roofer installing shingle over ridge vent on a roof

Leaky ridge vents may also indicate improper installation. You should address them right away to prevent any serious damage inside your attic.


Navigating Vent Pipe Issues: Uncovering Leak Sources


Homes equipped with pipes that vent through the roof can experience leaks during heavy rain. Vent pipes crack over time depending on the quality of the seal boot installed and its age.

old plastic pipe flashing with dry rotted gasket around the pipe

Always ask for premium vent pipes because cheaper pipe vents dry rot more frequently and can take up more of your time and money in repairs.  New products have been developed to prevent the need for frequent pipe boot replacement.

Skylights: A Common Culprit for Leaks


Many people dislike skylights because of their high tendency to leak during storms. No matter how tight the seal is, a skylight requires you to cut a hole in the roof. When you need natural light in a room they work miracles!


vented skylight from inside a home


Despite their water-resistant nature, skylights may start leaking after a few years due to natural wear. They can also gather up condensation and start leaking. To prevent this, you should call a professional roofing contractor to make sure they are sealed properly.


Chimneys and Caps: Tricky Areas Prone to Leaks


One of the most common causes of intermittent roof leaks is chimneys. They are prone to leaking and should be inspected frequently with the rest of the roof.  Chimneys get constant exposure to natural elements. Sun and rain.

brick chimney without a chimney cap

The heat difference between burning wood in the fireplace and the cooler outdoor temperature, chimneys have a high tendency to crack and cause roof leaks. This is caused by all of the expansion and contracting from going hot and then cold.


cracked flashing


Other leaks can result from a poorly designed valley that prevents water from draining around the chimney or the siding material on the chimney fails and causes a leak.

chimney cap with rust

Worn-out or rusted-out chimney caps and roof flashing are common causes of chimney leaks. Because the chimney caps are out of sight, we forget they need service too.  They should be addressed by your roofer immediately if they are rusted or have broken seals. 



When Storms Strike: Uncovering the Causes of Leakages


Some roofing materials can withstand greater impact than others. A possible cause of intermittent roof leaks is that your roof might be damaged due to hail, wind, or heavy objects falling on it.

Red boxes around hail impacts on an asphalt shingle

Another cause might be an accumulation of debris or even walking on your roof if it isn’t designed for it. If you suspect that your roof is leaking due to damage, get in contact with a reputable roofing company to conduct an inspection as soon as possible. 

Time's Toll: How Roof Age Leads to Leakage


Over the years, your roof is constantly exposed to weather conditions which causes it to wear out faster.  Although some roofing materials can last over a century with proper maintenance, most materials last about 20 years or less. 

roofing estimator inspecting a cornice return

A good rule to follow is to have roof maintenance at least once a year so that you know the exact condition of your roof and have time to plan before it starts developing serious problems. A little preventive maintenance can save a lot of interior repairs from leaks!


is a small roof leak bad


Addressing Your Roof's Intermittent Leaks: A Call to Action


The best time to get your roof fixed is now! Rip that bandaid off!

Now that you've confirmed you have a leaking roof, reach out to a local roofing contractor. Even if you can’t track exactly where the leak originates from, a roofer can. They'll fix the problem before it causes more serious damage to your home and belongings.

Whatever the reason may be as to why you haven't gotten your leaky roof fixed just yet. RoofCrafters resonates with you. Home improvement projects can be stressful, and asking for help can be hard. When you're ready to take that jump, we've got your back. You are only one step away from getting your leak to stop, click the button below to schedule your inspection.

If you're still feeling a little apprehensive and want to learn more about roof leaks and roof repairs, check out the extensive resources we have listed for you in our learning center. We recommend reading "The Most Common Causes of Roof Leaks", so you can better understand why your roof may be leaking.

Schedule an Inspection

David Toth

My name is David Toth and I am the lead estimator in North Florida with RoofCrafters Roofing. Originally from New Brunswick, I have called Florida home for the past 47 years. I enjoy cooking along with traveling to different historical areas in Florida when I have free time.