6 Reasons Your Roof Leaks in Heavy Rain

Experiencing a roof leak every time heavy rain is in the forecast is a stressful situation for any homeowner. What’s even more stressful is knowing what’s causing it in the first place and how to fix it.

You’ll never for 100% certainty what’s causing a roof leak until after a roof inspection. However, I can at least give you the common reasons a roof leak happens during heavy rain. 

For over 30 years, the team at Bill Ragan Roofing has provided honest and unbiased roofing information to homeowners like you. Now, we’ll help you determine what may be causing your roof leak. 

Let’s get to the 6 reasons your roof leaks in heavy rain.

1. Chimney issues

This first reason may not necessarily be an issue with the roof. But anytime there’s heavy rain or a prolonged period of rain, I can almost guarantee we’ll get calls about chimney leaks. 

There are a few different reasons why a chimney would leak during heavy rain. It could be that the integrity of the metal roof flashing surrounding the chimney is compromised.

If you have a brick chimney, it could be because of saturation in the mortar joints from prolonged periods of rain. This causes the mortar joints to become so saturated that water starts coming into the interior of your home. 

It can also be something as simple as water coming down through the top of the chimney. For a masonry chase top, there could be cracking from being wet and freezing. 

For a chase metal top, it could be from rusting, or its fasteners have come loose. A roofing contractor can take care of most chimney problems that have to do with the roof specifically. 

However, you’ll need to find a chimney company if there’s a problem with a chase top and/or spark arrestor. 

2. Rusted, cracked, missing, or improperly installed roof flashing

I already mentioned rusted or cracked flashing around a chimney can lead to a roof leak. But roof flashing is also installed in other important areas on your roof. 

This makes problems with roof flashing the second reason a roof leaks in heavy rain. The obvious signs of compromised flashing are cracks or holes from rusting in the metal. 

While this is a common reason a roof leaks because of roof flashing, I have also seen leaks caused by improperly installed roof flashing. There are even situations where roof flashing is left off a roof completely. 

Unfortunately, you won’t know the extent of the problem or if flashing is the main cause of leaks during heavy rain until after a roof inspection. But no matter what, all of these situations require some kind of repair or even a complete flashing replacement job. 

3. Pipe boot failure

The next cause of a roof leak (and most common roof leak in general) in heavy rain is when a boot around a plumbing pipe or another penetration fails. A boot goes around the base of roof pipes to ensure water doesn’t follow the penetration into your home.

The most common type of pipe boot on roofs today is made of a synthetic rubber called neoprene. Prolonged exposure to UV from the sun breaks down the neoprene, and the boot eventually develops cracks. 

Once it cracks or pieces break off, water runs down the pipe into the room below it (closet, kitchen, bathroom, etc.). Pipe boots should last around 10 years, depending on factors like location, weather, and animals.

But no matter what, pipe boots will not last the full lifespan of a roof. That’s why it’s important to get roof maintenance to catch problems with pipe boots before a leak has a chance to start. 

4. Improperly driven roofing nails

After pipe boot failure, this is the most common type of roof leak I see. The next reason your roof leaks during heavy rain is from popped-up nails or improperly driven roofing nails. 

If a roofing nail isn’t driven in far enough or is driven in sideways, the head of the nail works its way back up through the shingle. When this happens, rainwater catches the lifted nail as it comes down your roof and follows the nail inside your home. 

This not only happens to roof nails used for shingles, but I also see it happen with decking nails. No matter what installation method is used, as long as a nail hits good wood, holds tight and snug, and isn’t overdriven, then you shouldn’t have a problem 

5. Problems with your skylight

The next cause of a roof leak during heavy rain is a problem with your skylight. Skylights have a reputation for always leaking, but there are specific reasons a skylight leaks. 

Sometimes there’s a problem with a component or piece of the skylight. It could also be that the seal is worn down, and it’s time for a skylight replacement. 

But the main cause of a skylight leaking during heavy rain is improper skylight installation. Unfortunately, I see this happen frequently.

All it takes for this leak to happen is for an installer not to follow the manufacturer’s installation instructions. If this happens, you’ll have to take the cladding and flashing kit off, install ice and water shield around it, and put the flashing kit back on to give it the watertight seal it needs.

6. Sitting debris in roof valleys

Debris builds up in your roof valleys from a lack of roof maintenance. When this debris sits in a roof valley for too long, it builds a dam of leaves and sticks. 

When this happens, you have the potential for leaks during heavy rain. This dam of debris stops water from flowing down properly and causes pooling water to back up the roof. 

If this water backs up, it’ll find the path of least resistance (usually a backed-out nail) and could even get underneath your shingles. Just know that there are materials installed in roof valleys to prevent leaks. 

So, this may not happen until your roof is near the end of its lifespan. However, sitting debris on your roof will always cause problems if it’s allowed to sit there year after year. 

That’s why it’s important to get an annual roofing maintenance inspection to clear your roof and gutters of any debris. 

The tips you need to hire a great roofing contractor to fix these problems

There you have it, the main causes of a roof leak during heavy rain. While there are other reasons your roof could be leaking, these are the causes I see most often. 

But you won’t know what the cause or how to fix it until after an inspection by a roofing contractor. To ensure your roof is taken care of to the highest quality, you need to find a great local roofer. 

Unfortunately, this is harder than you may think. That’s why I want to give you the tips every homeowner needs to find the right roofing contractor for their roofing project. 

Since 1990, the team at Bill Ragan Roofing has provided high-quality roofing services to thousands of homeowners in Nashville and surrounding Middle Tennessee areas. Whether you need repairs or a full roof replacement, you’ll never have to worry about your roof again after working with us. 

Here are 7 Tips to Find a Great Roofing Contractor in your area to take care of your roof leaks.