How To Locate a Leak In a Metal Roof (Explained)

A typical metal roof is sturdy, water-resistant, and durable. However, metal roofs can still leak under some circumstances. Those with metal roofs are usually caught off guard when there are leaking issues on their roofs because they expect their metal roofs not to have leaks forever.

But this will no longer be the case because I will let you in on my research on locating a leak in a metal roof.

Understanding your roofing construction and the possible causes of leakages can help you find the leaky spots on your metal roof. It will help to also check for other signs of water seeping through into your home or external parts of your home.

Leakages within a metal roof will depend on the kind of roofing system you have. Some are made of continuous metal sheets, while others consist of metal tiles. However, Mother Nature can play havoc with either kind of metal roof, thus causing dents, punctures, corrosion, and fastener backups.

So, locating a leak on a metal roof may prove challenging. Once you locate the leaks, you should find the best ways of plugging them in.

In this article, I’ll discuss all the issues that revolve around leaks in metal roofs.

What Will Cause A Metal Roof To Leak In The First Place?

According to one McGraw-Hill Construction and Analytics survey, metal roofs are among the most popular roof choices. And about 48% of homeowners prefer this kind of roof because of its strength and longevity.

However, the strength of metal roofs doesn’t negate their ability to leak. To understand how leaks happen in metal roofs, let’s examine the key factors that cause the leaks.

Below are some of the primary causes of metal roof leaks:

1.   Improper Installation

Buying and installing metal roofing can be quite expensive. Depending on the type of roofing metal you choose and your location, it will cost you anywhere from $9,545 to $43,819 on average to install it.

Therefore, it may be tempting to cut corners by doing some problematic repairs or installations on your own or hiring an unskilled contractor. However, that would be ill-advised because one needs specific skills to perform these tasks. And you need to be knowledgeable enough to choose high-quality materials while you are at it.

If a roof is not well installed, it can loosen and even come off due to strong winds. In addition, the roofing panels may fail to overlap correctly, thus leaving gaps for water to seep through.

Poor installation may also lead to multiple issues with the roofing screws, which the contractor could drive in at the wrong angle or wrong depth. And some contractors may drive the screws into the roof so that they miss the wood framing below. When such things happen, water finds its way through the gaps in the washers and into the home.

Also, suppose your roofing contractor is not careful when using stack flashings to seal the area around the pipes that come through the roof for venting (examples include HVAC windows and plumbing pipes). In that case, water will either get into the spaces or pool there and causes corrosion. Some contractors also end up using incompatible materials to seal the openings on the roof. All these issues will end up causing leakages.

2.   Poor Quality Materials

The kind of roofing materials you use must be of the best quality out there. Low-quality washers will degrade quickly and leave the roof vulnerable to leaks. Also, if you use low-quality metal, it will rust or puncture easily within a short time, thus allowing water into your home.

Another material you need to worry about is metal sealants, which you use during metal roofing installations or repairs. They are usually used in areas such as Z flashings, metal ridge caps, and pitch pans. They tend to wear off faster than the roof on which they are applied. But low-quality products last for an even shorter time and could be the reason why your metal roof is constantly leaking.

3.   Wear And Tear

While the actual metal roofing panel or tile may last a very long time, some of the items used to install them won’t last as long due to wear and tear.

For example, winds may cause vibrations over a long period, making the roof fasteners back out. Also, the continuous freezing and expansion of water could cause contractions and expansions that make the fasteners back out and let water in.

Heat is also an enemy of the rubber washers, which are commonly used on metal roofs. Over time, the sun’s heat will cause them to degrade, and they will stop working as they were intended to.

4.   Physical Damage

While your roof is sturdy, it can undergo physical damage from hailstorms, fallen trees, and even flying debris, such as leaves. The damage may be in the form of punctures or dents. In addition, dents from foot traffic on your metal roof may arise from repairs or installation of vent pipes or skylights.

Physical damage to the roofing in the form of dents can cause the pooling of water. So, it impedes water flow and causes some of it to remain behind. Then pressure is exerted on the roof. If the area under pressure is located where two or more metal panels or tiles interlock, a misalignment may occur, thus causing water to seep between and into the home.

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Why Home Inspections Are Important

And even if the dented area does not cause misalignment, it may still end up leaking over time. That’s because the longer water remains standing on the roof surface, the more likely the roof is to rust over time. The rusty areas then become a point of weakness through which leaks can occur.

Signs Your Roof Is Leaking

You must know whether your roof is leaking before finding the leakage location and addressing the issue.

Below are some signs that water may be leaking through your metal roofing:

  • If the problem is quite severe, you may spot water dropping through the metal roofing whenever it rains or the snow begins to melt. But this is unlikely to happen if your home has a ceiling or attic.
  • While you may not see any sign of water drops, you may hear dripping sounds in your home.
  • Puddles of water may form on the floor underneath where the source of the leak is located.
  • Some of the items you store in an area with a leaky spot may end up damp or even moldy after the rains.
  • Water stains provide the most visible evidence of leakages on your metal roofs long after it rains or snows. These stains are usually ringed with brown and visible on the ceiling or roof sheathing within the attic.
  • Both the external and internal walls may have damp spots.
  • The paint on your walls may begin to bubble and peel every time it rains.
  • In the rooms where the leaks are, you may experience a musty odor.
  • There may be signs of mold or moss, especially on the outside of your property.
  • The wooden frames that support your roof may show signs of water damage, such as rot.
  • You may see missing metal shingles or debris from your roof on the ground or in the downspouts of your gutter system.

How Do You Stop A Metal Roof From Leaking?

How To Locate A Leak In A Metal Roof

It is not always easy to tell whether your roofing is leaking. Neither is it easy to find the exact spot through which water is seeping in. But once you determine that your roof is leaking, you can take some steps to find the precise source of the problem.

Below are strategies you can use to locate a leak in a metal roof:

  • Assuming you have an attic, you can go into the space with a flashlight and look around when it rains. If water is seeping through, it’s likely to be reflected due to your flashlight. Mark that area.
  • You can also get up on the roof and have someone tap the marked area when it’s dry, so that you can mark the leaky spot from the outside. Taking measurements by using the highest part of the roof or the edges can also help you find the site from the outside.
  • Investigate all the roofing areas where piping or other forms of penetration, such as a skylight are present. Check whether the rubber seals are as they should be. Also, do a visual inspection of the shingles, flashing, gaskets around the pipes, etc.
  • Do a visual inspection of the roof for any signs of dents, cracks, or punctures.
  • If you know where the leak has been happening, you can find the source from the outside by lifting the panels or tiles around the marked spot. Considering that water is subject to gravity, try to follow the upward direction to find the leak source from where the stains are located. You should also follow the sideways paths because the roofing can cause water to move in these directions.
  • If your roof has been affected by fallen tree limbs in the recent past, check out the affected area for punctures and dents.
  • Look out for areas of the roof where some of the metal panels or tiles may be missing or loose.
  • Watch out for objects sticking out on the roof. They may indicate that some things have come loose and created gaps for water to pass through.
  • Do a visual inspection of all the spots where the roofing tiles or panels interlock. Try to check whether anything is loose or backed up. If the pieces are not tightly interlocked, it could be indicative of a significant problem.
  • Check the your gutter and downspouts for signs of debris from the roof. It means parts are falling off, and the roofing will not fully protect your home.
  • Discoloration or degradation of your metal roofs may indicate rust due to the constant accumulation of water. That area is likely to be weak and serves as a water entry point.
  • If you notice from the ground that your metal shingles are buckling or curling, it may indicate that moisture is getting trapped underneath, which means water could be getting in.
  • Investigate whether the roofing sealant is present or missing within the roofing areas where it was applied. The sealant may also be present but decaying. All these sections serve as points of water entry.
  • If you cannot see any signs of leaks, work with someone. One of you should get on the roof with a garden hose and pour water all over the metal roofing in stages. The second person should be inside, carefully watching the underside of the roof for signs of leakages.
  • If you can see the signs of a water leak or have a gut feeling that your metal roofing is leaking but cannot find the source of the leaks, it would be wise to call in the big guns. A professional home inspector not only knows what signs to watch out for but can also conduct inspection better and let you know the true extent of the damage. Ideally, it would help if you had roofing inspections twice a year, no matter how strong your metal roof appears to be.

Once you identify a leaky spot on your metal roof, you need to plug in the source of that leak. The method you use to do this depends on what the problem is. Some of the options available to you include the following.

1.   Use A Sealant

Some roofing problems that cause leaks are simple to address. Others require additional reinforcements. Such issues may require the use of a sealant of some kind. If some small gaps and cracks need fixing, sealants come in handy. You can also use them to seal joints on the roofing. Any metal-to-metal connections which are not fastened, including Z-closure sides, would benefit from sealants.

Most sealants consist of either polyether or silicone. And they come in various colors that match the color of the existing roof. However, the latter is better for darker roof colors that absorb much sun and, thus, experience more heat.

Examples of excellent sealant products include Titebond metal roof sealant and Butyl Tape.

2.   Repair Affected Roofing Parts

Some roofing parts may need repairs. These include under-driven or overdriven screws, backed-up fasteners, misaligned roofing panels, and flashing edges, among other things. The issues affecting these roofing parts will determine how they are fixed.

For example, misaligned metal roof panels may need to be readjusted and reinstalled. And if the flashing on the roof has small holes, these could be patched up using roofing cement. And those whose edges stick out can be flattened and then nailed down after applying roofing tar. Finally, you can caulk the edges and seal them to prevent future leakages.

3.   Replace Affects Metal Roofing Sections

If some sections of your roof are missing, replacement is the only option. You can also replace badly corroded roof flashings and panels.

In addition, you can replace roofing fasteners and washers, which have backed up or deteriorated, with new ones. You can also remove old metal sealants and recaulk the joints that need sealing.

Final Thoughts

Whenever you suspect a leak in a metal roof, investigate transition and termination points on the roofing first because they tend to be weak points. In addition, you should pay close attention to areas around roof penetrations. And if the body of the roof is not as it should appear, that may also be a sign of a water leakage problem.

However, it is not always easy to locate a leak in a metal roof. So, consider regular home inspections that can help you deal with leaks before they become severe. Hiring a professional inspector gives you a better sense of the problem your roof has. And you can deal with it early and solve it once and for all, thus saving money in the long term.

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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