6 Metal Roof Common Problems and How to Avoid Risks

Metal roofs are popular because of their durability and longevity. While a conventional asphalt shingle roof will last for 20-25 years, the average lifespan of a metal roof is 50 years. Some will even last for more than 100 years.

However, metal roofs are not immune to problems. That's why regular maintenance is crucial. You can mitigate some common issues through regular maintenance, but others necessitate elaborate interventions. Below, we look at the seven common metal roof problems and how to avoid them.

1. Oil Canning

Oil canning is a visual phenomenon that makes metal panels appear wavy and distorted on the flat areas. It is an inherent problem in metal roofs that is hard to avoid and control. That's because it is difficult to trace the exact source of the problem in many cases.

metal roof oil canning

Luckily, oil canning is merely an aesthetic issue and does not affect the structural integrity of the metal panels. Nevertheless, it lessens the overall curb appeal of your home or building, and you should avoid it all the same.

Several reasons could put stress on the metal panels, thus resulting in oil canning. They include:

Reason 1: Thermal Expansion

Metal roofs will inevitably expand and contract due to temperature fluctuations. Therefore, your contractor should take measures to accommodate this movement. These include using the right clipping system and pinning the panels only at one end. Otherwise, lack of adequate space will stress the panels and lead to oil canning.

Reason 2: Installation Errors

Metal roofs are arguably one of the most challenging roofing systems to install. It requires specialized skills and tools that not all installers will possess. As a result, metal roof installation mistakes will occur. For instance, screwing the fasteners too tight can stress the metal panels, resulting in oil canning.

You can minimize metal roof installation mistakes by hiring contractors with the relevant training and experience. Also, you should follow up to ensure the installer adheres to the recommendations of the manufacturer throughout the installation process.

Reason 3: An Uneven Deck

An uneven deck will also lead to oil canning, no matter how flawless the installation process is. Therefore, it is important to assess the condition of the deck before installation commences. Should your installer spot any inconsistencies, it is imperative to address them first to avoid future problems.

Reason 4: Improper Handling and Storage of Panels

The contractor should take care when carrying and storing metal panels. Otherwise, they risk twisting and stressing them, increasing the chances of oil canning even before installation commences. Similarly, they should take care not to stress the panels during cutting and roll forming.

How Can You Avoid Oil Canning?

As we mentioned earlier, oil canning is hard to avoid since it is difficult to define and measure. However, there are several measures you can take to reduce the chances of it occurring. Breaking up the flat surface using ribs and striations is one of them-the lesser the flat surface, the lesser the likelihood of oil canning.

Opting for thicker panels is also advisable since thinner panels are more prone to the problem. You can also hide the effects of oil canning by avoiding high gloss finishes. Matte finishes are less reflective and will make the issue less visible.

2. Scratching and Scuffing

metal roof scratching

Contractors often take care to protect the surface of the metal before, during, and after installation. However, mistakes are inevitable, and some form of surface-level damage is likely to occur. Scratches can occur because of any of the following reasons:

  •  Mistakes during cutting and roll forming
  • Improperly handling the panels
  • Lack of proper storage
  • Dropping tools on the roof during installation
  • Foot traffic during and after installation
  • Fallen branches during storms

Minor scratches that merely penetrate the top coating can be unsightly, but they rarely cause major problems. You can easily remedy such using a paint touch-up pen.

Should you choose this route, only use paint pens from the manufacturer to ensure it is of the same color as your metal roof. Trying to match pens from other sources with the color of your roof will almost always fail.

If the scratch is deep enough to expose the bare metal, a touch-up pen will not be sufficient. In such a case, contact your manufacturer as soon as possible. The more you wait, the more you expose your roof to damage such as corrosion.

How to Avoid Scratches

There is little you can do to avoid scratches that occur before and during installation. Here, your best bet is hiring qualified installers who are trained to prevent, identify and remedy any damage to the surface of the metal.

It is upon you to identify, remedy or alert your manufacturer for scratches that occur after installation. 

It is also essential to minimize traffic as much as possible, but if you have to walk on the roof, ensure your shoes are clean since dirt and debris can cause scratches. Additionally, avoid stepping on weak points such as valleys and ribs.

3. Corrosion

metal roofing Corrosion

Metal roofs usually have coatings that increase their corrosion resistance. For instance, Galvalume steel includes a zinc alloy plus an aluminum coating. Moreover, metal manufacturers employ paint systems such as polyester and PVDF to shield the metal from corrosion.

Despite these measures, corrosion can still occur due to a variety of factors. These include:

Reason 1: Scuffing and Scratching

Foot traffic, fallen branches, and installation errors can result in scuffing and scratching. This strips the surface of the coatings and paint, exposing the metal to corrosion. Refer to the tips above on how to avoid scratches.

Reason 2: Underside Corrosion

While coatings and paint systems shield the upper surface of the metal, the underside is not always as protected. Although it is not exposed to the elements directly, water can still seep through weak points and corrode it.

Rough underlayment or installing the panels over shingles can also strip the underside coating and accelerate the corrosion process.

You can avoid underside corrosion by using panels with an underside coating and avoiding granulated underlayment. If you intend to install metal panels over shingles, ensure you put a barrier in between to protect the panel's backside.

Reason 3: Cut Edges

Cutting and roll forming metal panels will leave the edges bare, thus exposing them to the elements. Your contractor can mitigate this problem by hemming or folding the edges to avoid exposing the cut edge. If that is not possible, they can use a paint pen to coat the exposed edges.

How Else Can You Deal With Corrosion?

Identifying corrosion before it spreads is essential. That means regularly checking your roof for any potential signs of corrosion. You should also clean the roof annually to avoid dirt and debris accumulation, which may corrode the surface.

If you notice any signs of corrosion, it is imperative to get in touch with the manufacturer as soon as possible. They can remedy the problem before it spreads to other parts of the roof.

4. Dissimilar Materials

When a dissimilar material gets in contact with your metal panels, the less active material can stain, corrode and degrade your roof when it gets wet. In the worst-case scenario, it can cause a total system failure.

metal roofing Dissimilar Materials

As a result, metal panels should not get in contact with materials such as copper, concrete, iron, or lumber. These are often present in gutters, pipes, rivets, sidings, chimneys, air conditioners, etc.

Sometimes the panel need not be in direct contact with the material. A simple run-off to the metal is enough to cause irreparable damage.

It is essential to talk to your contractor before installation about avoiding dissimilar materials. But if it is not possible to steer clear of them, they can take measures to prevent direct or indirect contact with the panels.

For instance, they should never allow the materials to get wet. Furthermore, they should place a barrier between the two to avoid chemical reactions.

Water leakage is a common metal roof problem that is hard to detect. If you have a water-tight underlayment, sometimes you won't notice the issue until the damage is beyond a simple fix. Leakages are either caused by human error or extreme weather.

Reason 1: Human Error

Human errors that may lead to leakages usually occur during installation. These include misapplied sealants, misaligned or improperly secured panels, and improperly installed fasteners.

Since such problems are hard to identify before the fact, you can only protect your roof by hiring qualified contractors with the relevant experience.

You should also ensure their installation process matches that from the manufacturer. Failure to adhere to manufacture specifications will not only increases the chances of leakages but can also void your warranty.

Reason 2: Weather Conditions

Heavy snow, wind, and rain could overwhelm your roofing system, resulting in leakages. Therefore, it is essential to perform regular checkups, especially after experiencing extreme weather conditions. Catching the problem early can nip it in the bud and avoid an expensive metal roof leak repair process.

Thermal expansion is another issue you should not ignore, especially with an exposed fastener system. Temperature fluctuations can cause fasteners to back out, thus creating potential areas for leakages. Again, you can mitigate the problem with regular checkups.

How to Deal with Leaks

If you notice any leaks or potential leakage areas on your roof, notify a metal roof repair specialist as soon as possible before the issue gets out of hand. That is supposing you don't have metal roof leak repair experience. Just like with corrosion, the earlier you fix the problem, the better.

5. Chalking and Fading

Chalking and fading are metal roof problems that are often beyond your control. Chalking is when the paint resin on the metal panels breaks down due to UV exposure, leaving a whitish residue. On the other hand, fading refers to the gradual process where the paint pigment breaks down, resulting in color degradation. The phenomenon is often caused by UV exposure, water, pollution, or chemical damage.

metal roofing Chalking and Fading

Although these two processes are inevitable, the extent of their effect will depend on the prevailing environmental conditions. Nevertheless, the situation is not unmanageable. There are still measures you can take to maintain the original look of your metal roof for longer.

Best Paint System Choice

The most important is choosing the best paint system for your environment. The choices include:

Polyvinylidene Flouride (PVDF)

This paint system is often referred to as Kynar 500 or Hylar 5000. It is the best paint system the market has to offer and will hold up best against extreme weather. Consequently, it attracts the longest chalk and fade warranties. However, it is also the most expensive option.

Silicone-Modified Polyester (SMP)

SMP is also another quality paint system, but it is not as good as PVDF. It will stand up to extreme weather conditions and will attract a chalk and fade warranty of up to 35 years.


Polyester is the least performing paint system on metal roofs. However, it is also the least expensive and could work in areas that experience mild weather conditions. As you can expect, it can only attract a chalk and fade warranty of up to ten years.

How to Deal with Chalking and Fading

As we have established, chalking and fading are unavoidable. They are bound to occur no matter where you live. The important thing is to choose the best paint system for your environment. If you are unsure, you can always ask your manufacturer for help.

Remember, cleaning and maintenance can prolong the life of your roof. However, always follow the laid-out instructions to avoid damaging your roof's paint system.

If you perceive you have a legitimate claim concerning chalking and fading, contact the manufacturer first. Don't attempt to deal with the problem on your own.

6. Noise When It Rains

Do metal roofs make noise when it rains? The short answer to this question is yes. A metal roof can be noisy when it rains. However, if you have solid roof decking and insulation, you can lessen the noise significantly.

This one seems like a minor problem compared to others on this list. However, noise is a major concern for some people.

How Can You Stop the Noise?

Unfortunately, you cannot stop the rain noise on your roof. The best you can do is dampen it. As we mentioned, a solid roof decking can absorb most of the sound. But you can dampen the noise further by installing wood fiber insulation boards.

If the noise bothers you too much, installing the boards between the panels and your deck can provide an extra layer that will absorb most of the sound.


Metal roofs are arguably one of the best roofing systems in the market. It is no wonder they have gained so much popularity in recent years. However, the disadvantages of metal roofs are rarely talked about. Above, we have listed some common metal roof problems and offered tips on how to deal with them.

In summary, the best way to deal with metal roofing issues is through regular cleaning and maintenance. That can help detect problems before they get out of hand. However, you can avoid most of these issues by hiring qualified and experienced contractors. Many problems are a result of metal roof installation mistakes.

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