The 6 Most Common Roof Leaks (Causes, How to Repair, & More)

There are few things more concerning as a homeowner than a roof leak. This leaves you scrambling to find the source and a solution before the dam breaks.


Unfortunately, there are plenty of reasons your roof could be leaking. It could be caused by improper installation, material failure, storm damage, and so much more.

However, there are common roof leaks we see and repair on a regularly. So, let’s start there.

At Elite Exteriors, we believe in using our 30-plus years in the roofing industry to help homeowners deal with stressful roof leaks. But even if we can’t be there to physically help, we can still provide transparent and helpful information.

In this article, you’ll learn the 6 most common roof leaks, where they’ll show up in your home, and how to repair them. I also break down what you need to know about repairing the roof leak yourself.

1. Pipe Boot Failure

The most common roof leak is when a boot around a pipe fails or another penetration. A pipe boot is a type of roof flashing that goes around the base of the pipes coming through your roof.

While there are different types (lead, plastic, copper, etc.), the most common is a neoprene (synthetic rubber) pipe boot. But no matter the material, its main job is to prevent water from following the pipe down through your roof and into your home.

Because a neoprene pipe boot is the most common, let’s use it as an example. Over time, UV from the sun breaks down the neoprene and it cracks. Once it cracks, water follows the pipe into whatever roof it’s above.

Just know that pipe boots will not last the full life of the roof. They should last around 10 years, but different factors (location, weather, animals) ultimately determines when they’ll need to be replaced.

Where will the roof leak show up?

A roof leak from pipe boot failure will show up below wherever that pipe is located on the roof. It mainly shows up in a bathroom or closet, but it could also be above a master bedroom or another room.

You’ll actually be able to track this leak by looking in the general roof area above the room to determine if the pipe is causing water to get into your home.

How is the roof leak repaired?

The simplest way to repair this roof leak is to install a little rubber collar over the top of the old cracked neoprene pipe boot. The collar will encase the existing flange (the flat rectangular flashing around the bottom of the pipe) and should last you another 10 or so years.

before and after repair on a roof leak caused by pipe boot failure

But when getting a new roof, you’ll replace all the pipe boots completely.

2. Improperly driven nails

The second most common cause of roof leaks is when a roofing nail backs out through a shingle. If a nail isn’t driven in far enough or driven in sideways, the head of the nail eventually work its way up through the shingle.

nails backing out through asphalt shingles

When it rains, water coming down your roof catches the nail’s head and follows it down to the inside of your home. This doesn’t happen just with roofing nails used on shingles, but also decking nails.

If the decking nail didn’t hit wood when the framing was done, the sun can draw the nail out through the shingle. Whether it’s air-nailed or hand-nailed, if the nail hits good wood, holds tight and snug, and isn’t overdriven, you shouldn’t have this problem.

This makes choosing a roofing company with a great and proven installation history crucial to avoid this roof leak.

Where will the roof leak show up?

The location of the improperly driven nail is where the water will drip down in your home. So, this roof leak can literally show up anywhere in your home. 

You could even have multiple roof leaks depending on how many nail heads are sticking up.

How is the roof leak repaired?

To repair this leak, the roofer will break the seal on the shingle, lift the shingle up, pull the underdriven nail out, and move it. If the nail wasn’t driven in straight, they’ll pull the same nail out, drive it in properly, and then lay some ice and water shield on top of it.

They’ll also reseal the shingle after repairing the nail that worked its way through it. If the decking nail didn’t hit wood, it’s just a matter of moving the nail over so that it catches the rafter.

After moving the nail, they’ll fill hole with sealant to reseal the shingle back down.

3. Debris in gutters that stop above a roof-line under a valley

A roof valley is when two slopes meet in a V shape that allows water to flow down a roof into the gutters. On most roofs, roof valleys runs right down into the gutters at the eaves (gutter line).

gutter in a roof valley

But on others, a gutter is installed in a valley that stops in the middle of two slopes. If this gutter gets filled with leaves and other debris, water finds the path of least resistance into your home. 

gutters dying into a roof valley on an asphalt shingle roof

This won’t happen under normal circumstances, and may take a heavy rain to show up. However, neglecting roof maintenance and not clearing the roof of damaging debris makes this roof leak more common.

Where will the roof leak show up?

For this specific roof leak, the problem is the fascia (board that runs along the eaves/gutter line). If there’s no flashing applied to the fascia board, it’s not if it’ll leak, it’s when.

Once the water gets under the soffit and behind the gutter, it can go anywhere to cause all kinds of damage. This means a roof leak will show up in the room, walls, or wherever the gutter is.

How is the roof leak repaired?

The roof leak is repaired by simply adding flashing to prevent water from getting behind gutter. This is done by loosening the gutter to install 3 pieces of flashing behind the gutter and onto the roof with the last piece tucked under the valley.

4. Chimney wear and tear

While not exactly a roof leak, the next common leak is actually multiple chimney problems. It could be leaking from problems with the flashing under the shingles surrounding the chimney.

If its brick, it could be the mortar joints. If it rains for a few days, the mortar joints and even the bricks themselves get so saturated that water comes into the interior of your home.


saturated chimney with moss growing

There’s also problems with water coming through the top of a chimney. This could be from a masonry top cracking from being wet and freezing or a metal top rusting over or the fasteners have come loose.

rusted chase top on chimney

If you have a chimney with siding, water can get in the corners where the siding butts into the corner boards. Not only does this rot the boards on the outside, but also the wood behind the chimney you can’t see.

rotten siding from leaks caused by water getting behind the wooden boards

Whatever the reason your chimney is leaking, you won’t know the extent of the damage or the cause until a roofer gets up there and does an inspection.

Where will the roof leak show up?

Obviously, a chimney leak will show up around the fire place in your home. However, the area where water is coming from sends it a couple different ways.

water damage to wall around fireplace from chimney leak(Water damage to walls from leak around chimney)

If it’s leak caused by flashing problems or a saturated chimney, water will get into the walls around the fireplace. For leaks caused by damaged chimney caps, the leak will drip inside the fireplace every time it rains.

How is the roof leak repaired?

Repairing a chimney leak depends on the problem. If the leak is from flashing problems, the roofer will reflash the area around it.

If it’s from the mortar joints, they’ll have to apply a masonry water repellent to seal it. To repair leaks from chimney siding, you’ll actually have to hire a competent carpenter or siding man.

For a leaking chase top on a chimney, you’ll need to hire a licensed chimney sweep company for repairs. This is because most roofers don’t have the proper licenses and, more importantly, the insurance to perform this kind of work.

However, a roofer can diagnose the problem to determine if you’ll need to hire a licensed chimney sweep to handle the repairs.

5. Improperly installed skylights

Skylights have bad reputation over the years because there’s the misconception that they all leak. Now, there are times when it leaks because a component or piece of the skylight fails.

leak around skylight caused by improper installation(Leak caused by improperly installed skylight)

However, the main cause of a leaking skylight is an installer not reading and following the manufacturer’s installation instructions. Unfortunately, I see this leak frequently to the point that it reflects poorly on the roofing industry and skylight companies.

Where will the roof leak show up?

A skylight leak shows up wherever the skylight is located in your home. But how it shows up depends on where it’s leaking.

If it’s from the flashing around the skylight, the roof leak will damage the dry wall around the skylight. If it’s a problem with a component or a piece of the skylight, you may have water dripping on whatever is below.

How is the roof leak repaired?

Repairing a skylight leak requires taking the cladding and flashing kit off, putting ice and water shield around it, and then putting the flashing kit back on. This ensures there’s a watertight seal that’s needed to keep water out.

6. Collar failure around a gas vent

The last common roof leak is a collar failure around a gas vent. This metal pipe with a cap comes through the roof to ensure any carbon monoxide coming from gas appliances vents out through the roof.

collar failure around gas pipe vent

These vents are usually installed by HVAC workers after the roof the roof is completed. But because they don’t know proper roofing techniques, they’ll only slide a collar over an unsealed pipe thinking it will shed the rain.

Under normal circumstances, this works. But with a torrential downpour, water can splash under the collar and lead to water running down the pipe. 

Where will the roof leak show up?

Just like pipe boot failure, this roof leaks shows up around the appliance connected to the gas vent pipe. The last thing you want is carbon monoxide in your home, so don’t try to do anything around the vent yourself.

It’s better to leave it up to the professionals for you and your family’s protection.

How is the roof leak repaired?

Because this roof leak is around an HVAC component, it’s difficult and a little tricky for a roofer to repair. They will very carefully raise the collar up, seal it with a dark color caulk, and then slide the metal collar back down into the sealer.

Because of the carbon monoxide potential, roofers have to be very careful when trying to repair this leak to prevent it from going inside a home.

Should you try to repair your roof leak?

If you’re a handy person or have construction experience, you can probably repair some of these roof leaks yourself. Especially with all the videos, articles, and other resources that can help guide you through the repairs.

Just be warned, repairing these incorrectly can lead to much bigger and costly problems. The quality of doing it yourself versus a certified roofing contractor can be drastic.

Your safety is another thing to keep in mind before trying to repair a roof leak yourself. If you’re not used to being on a ladder or walking on a roof, you shouldn’t be up there, period.

No matter if you try do repair the roof leak yourself, you should definitely have your roof inspected and maintained on an annual basis. This will actually catch most of the problems in this article before they leak inside your home.

How much will it cost to repair your roof leak?

After reading this article, you know the most common roof leaks, where they’ll show up, and how they’re repaired. You also have my opinion on whether you should try to repair a roof leak yourself or call a professional.

I understand wanting to do your own repairs, especially from a cost-saving perspective. But before jumping on YouTube and heading to Home Depot, you need to know how much roof repairs actually cost. The last thing you want is to do more damage or hurt yourself to save a couple hundred dollars.

The Toughest Question in the Roofing Industry

Do you Need Repairs or a Full Roof Replacement?

Contact Elite Exteriors for your FREE roof inspection today!

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