an flat roof on a high building

3 Metal Roof Problems to Watch For

A metal roof is one of the more durable roofing options you can place on your home, but it is not immune to problems. Fortunately, you can reduce or eliminate issues by knowing the most common problems that can occur with your roof. A watchful eye combined with a quick call to a roofer can fix a small problem before it becomes a big deal.

1. Corrosion

Corrosion and rust can be a major concern when it comes to metal roofing. Modern metal roofing is designed in a manner to help reduce these issues, but they are still something to watch for.

Cause

Metal roof panels are typically made from steel, aluminum, or a zinc alloy. The panels are either galvanized or coated (including paint) to help reduce the chances of rust and corrosion. If the coating fails, then degradation can become an issue.

Inadequate separation between the roof material and other components can lead to problems. For example, contact between two different metals can cause corrosion (called electrolysis), as can contact between certain types of metal roofing panels and chemically treated lumber.

Repair Options

If you spot corrosion or the possibility of corrosion on your roof, you need to bring in a repair technician. Any current rust or corrosion must first be addressed. Your roofer will likely sand off the damage and then apply a protective coating to prevent future issues. If the area of damage is more extensive or inaccessible, it may be necessary to remove a portion of the roofing system to effect a repair.

They will then install a buffer between the metal and the corrosive material. This is typically done by applying a polymeric membrane material or coating over the metal or other material so that there is no longer any direct contact that could lead to corrosion.

2. Buckling or Waviness

Metal moves when exposed to heat or cold. The expansion and contraction may result in what is known as “oil-canning,” commonly observed as what appears to be buckling or waviness in the metal panels.  This is generally an appearance issue and does not indicate a functional problem with your roof.

Cause

Oil-canning is caused by stress, which is often introduced into the roofing panels at the time of production or when the sheets are cut for installation. Thinner metal panels can be more prone to oil-canning compared to thicker materials.

Oil-canning may also occur due to installation issues, such as unevenness in the roof decking, attachment alignment problems, or temperature fluctuations during installation.

Repair Options

Repair options are either replacement or camouflage. If you choose to replace, then opt for heavier-gauge, tension-leveled panels since these are less prone to oil-canning. Your roofer can also install the metal with expansion clips, which provide more give and minimize oil-canning from temperature fluctuations.

If you choose to live with oil canning, you can have the roof repainted to help minimize the visibility of material irregularities. Low-gloss paints de-emphasize oil-canning more than higher gloss treatments. Textural paints can further camouflage this concern.

3. Leaks

Often, people choose metal roofs because of their durability and damage resistance, but that doesn’t mean that a metal roof can’t develop a leak. Just like any roofing material, leaks are a possibility and you want to catch them early before they cause damage inside the home.

Cause

Most metal roof leaks stem from a failure of either a seam or a fastener. A metal roof is typically made from several panels that are attached together at seams. The standing seam style is common, but there are other types of seams.

On exposed-fastener systems, the fasteners can also begin to back out over time, which can lead to a leak. You can usually spot failed fasteners from the top of a ladder, as you can easily see the raised or missing screws.

If water is able to get beneath the metal roof system, there is greater opportunity for the water to enter the building beneath through a penetration, underlayment lap, or seam.

Repair Options

Seam leaks can typically be repaired by re-sealing the seams with butyl tape and waterproof roof caulking. A roofer can apply these fresh seals in such a manner so they do not detract from your roof’s appearance.

Fastener issues may require a bit more effort. The existing fasteners may need to be tightened, or some cases replaced with larger diameter fasteners to secure and seal the roof system.

Contact SUNVEK for more help with your metal roof.

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