Why Some Metal Roofs Corrode Faster Than Others

Posted on: 21 May 2019

Corrosion weakens the roof, increases the risk of leaks, and also discolors the roof. Some roofs seem to suffer corrosion faster and more seriously than others. Here are some of the triggers for accelerated corrosion on metal roofs.

Contact with Dissimilar Metals

If two dissimilar metals come into contact, under the right conditions, one of them is likely to suffer accelerated corrosion. The phenomenon is known as galvanic corrosion. The right conditions, which are available in almost all roofs, are moisture and air. Therefore, don't introduce another metal to your roof if you don't want the roof to corrode first. For example, don't use a different metal for flashing or for roof repair.

Dirt and Debris Accumulation

Moisture accelerates corrosion so a metal roof that is always wet will corrode fast than a roof that is always dry. Your roof is likely to be constantly wet if it is always covered in dirt and debris. For example, if you have large trees around the house, their leaves may fall on the roof, accumulate and trap moisture.

The moisture issue is also the same reason flat roofs tend to corrode faster than pitched roofs. Drainage problems are common with flat roofs because the action of gravity is reduced.

Poor Anti-Corrosion Treatment

Roofing manufacturers understand the threat of corrosion and coat their products with anti-corrosive treatments. Unfortunately, these treatments are not always equal, and some manufacturers make them better than others. Thus, a low-quality roof may suffer corrosion faster than a high-quality roof. Not only that, but a defective roofing product may also lose its anti-corrosive treatments fast and encourage corrosion. In such cases, your manufacturer's warranty may come to your rescue for the roof repair.

Poor Maintenance

Failure to maintain your roof also accelerates its corrosion. The anti-corrosive treatments of metal roofs don't last forever. Over time, you may need to apply another coating or paint the roof to prevent corrosion. Also, damaged parts of the roof are likely to corrode because the damages (such as curt and punctures) expose the untreated metal surfaces.

Disadvantageous Locations

Lastly, some roofs also corrode faster due to their environments. For example, roofs in coastal areas suffer corrosion due to their exposure to salt water (salt is a corrosion catalyst). Roofs in industrial areas may also suffer accelerated corrosion due to the chemicals in the air.

Before you install a metal roof, talk to your roofing contractor about the anti-corrosive measures you can take. If you are already dealing with corrosion on your metal roof, call a roofing contractor for a diagnosis and solution of the problem. To learn more, visit websites like http://www.us-roofing.com.