Corrosion On Your Commercial Roof And How To Effectively Deal With It

As we know from many years of practice and experience, perfectly installed commercial roofs are incredibly durable. They are designed to last for decades, if not for several lifetimes. But commercial roofs, since they are made from iron-based metals and frequently exposed to rain and moisture, suffer from rust corrosion. The durability of a commercial roof highly depends on the practices that we put into place. 

Because of its extreme durability and flexibility, steel has been the roofing material of choice for commercial roofs in Australia for a long time. But the direct exposure to rain, moisture, and other environmental reactants can cause rust corrosion and damage steel within a short period of time. With the advancement In technology, roofing materials made with steel today are coated with effective layers that avoid the direct exposure of steel to moisture and environmental reactants so they resist moisture damage for years. However, some installation errors and external damages can cripple the external coating and expose the steel to the environment. If it goes unnoticed for a long period of time, the corrosion it ensues becomes highly challenging to fix. It can even become a serious safety hazard in the worst case.

Do you know that most cases of roof leaks occur because of corrosion? That’s why in order to deal with the leaks in the best way, you have to understand corrosion and how to effectively deal with it. ADESA presents a guide to understanding corrosion on your commercial roof and how to deal with it effectively.

All the smaller issues that go unnoticed for a longer period of time become a huge challenge to the whole commercial structure in future. From tiny leaks to damaging to the whole roof, unnoticed corrosion can harm a commercial roof in so many ways. 

Corrosion on commercial roofs, however, is inevitable. Even the roof made from the best roofing material is vulnerable to corrosion as its service lifespan is near the conclusion. Apart from that case, other types of corrosion can be dealt with effectively with the right practices. 

Commercial roofs that are severely damaged will need to be replaced or thoroughly refurbished even if they haven’t reached the end of their lifespan. This mostly happens because of negligence and wrong practices. There are several factors that contribute to corrosion besides the lifespan of roofing materials. And with the right approach, most can be taken care of. A little consideration can help you save a lot of money in the long run.

Factors To Consider To Understand Corrosion On Commercial Roof 

With the advancement in technology, today’s quality roofing materials offer unmatched protection against corrosion. Having said that, there are several practices that, if not considered carefully, can lead to unnoticed errors that lead to corrosion. While installing the brand new roof, the use of the right material according to the environment and the operational requirements is the first thing that helps you deal with all your roofing problems effectively. On top of that, regular inspection and care of your commercial roof are also very important to run it as efficiently after years of installation.   

Location And Environmental Factors 

The reaction of the core elements of roofing materials with moisture and other environmental factors is the first thing you would want to talk about when it’s about corrosion on a commercial roof. Environmental factors tend to change with the location so corrosion on your roof can be different according to where your commercial building is located. You will first need to understand the various weather elements of your building’s location that contribute to the corrosion of your roof before choosing the roofing material and design.    

Even in a moderate environment, moisture and rain react with the elements of your commercial roof and cause corrosion. The scenario gets tougher under a harsh environmental condition. If your commercial building is located in an area where there is a higher level of salinity and where off-gassing and toxic emissions exceed normal conditions, there is a higher chance that your roof faces corrosion. Rainwaters are generally slightly acidic, but the presence of acid in rainwater is different according to different locations. The more acidic the rain, higher is the chance of corrosion on the commercial roof. Acid and other chemicals can weaken the coating of your roof faster and expose the core elements to the moisture and rain. 

Roofing Materials

Well, it’s not a surprising statement if someone tells you that with quality materials you get better results. For broader benefit, however, you should be able to choose the right roofing material that delivers you the best value. Since corrosion on your commercial roof is primarily linked with the environmental factors depending on your location, you should choose the right material according to the environmental severity of your location as well as your operational requirement.  

Apart from the addition of special features for the harshest conditions, good roofing materials should possess a minimum property that can effectively deal with the environmental factors and prevent corrosion for its operational lifespan. The steel should meet the minimum national standard for quality and have anti-corrosive layers of zinc and aluminium with an effective paint finish. Most of the quality roofs have multi-layered PVDF paint coating on their weather side.   


Although it might not be as hard as we think for the experts who have been doing it for years, installing a roof is a complicated process as even small details need to be carried out perfectly. Bad installation practices can lead the roofing materials exposed to the environment, contributing to corrosion. Cut-edges and overlapped areas are more prone to corrosion if there is lack of professionalism during the commercial roof installation

Roof sheets are normally cut to length to suit the building layout. Where the cuts are made is basically where the corrosion is most severe. With cut-edge on the sheets, a small amount of steel is exposed to the weather. It is very critical that this area is as small as possible and very crisp clean without a jagged or rough edge. Cutting the steel roofing with a saw blade during the installation is not a very wise idea as it can leave a very wide exposed edge to the steel. When the cut is crisp, a very little amount of steel is exposed and that area is protected from corrosion as soon as the rain starts. 

Whenever we talk about new installations, we should also mention the installation of the other systems and components such as gutters and downspouts, insulation and ventilation etc. that support the whole roofing system. Failure to properly install gutters and downspouts on and around the roof also increase the chance of moisture getting in contact with the elements of the roof and create the reaction to contribute to corrosion.

3 Types Of Corrosion You Should Know About 

Basic corrosion in the roofing materials occurs because of regular chemical and electrical processes. Positively charged iron ions bond together with negatively charged water ions to ultimately form brown rust through a chemical process. The reaction continues as long as the iron and water molecules are exposed to one another until all that is left is a pile of brown rust.  

Bimetallic corrosion occurs when a chemical reaction is caused between two different metals that come into contact. This type of corrosion may occur in the areas where there is the overlapping of roofing sheets as it can be partly dependent upon any two metals’ positions. 

Environmental corrosion is more common in the roofing surfaces that are located in coastal environments where there is a higher level of salinity and those in industrial or manufacturing areas where off-gassing and toxic emissions exceed normal conditions. That is why the use of high-quality materials as well as a proper coating in the roofs according to the specific environmental challenge is essential.  

Prevent Corrosion On Your Commercial Roof With Simple Considerations

Technology has made it easier to prevent corrosion on your commercial roof. That being said, negligence and failure to regularly care for the roof according to expert’s advice will ultimately lead to various problems in your roof, let alone corrosion. It might be easier said than done, but the preventing reaction between iron and water – the major contributing factor for corrosion – alone can contribute a lot in preventing corrosion. But we have to understand different aspects of commercial roofing to deal with corrosion effectively.

Choose The Right Roofing Material 

High-quality materials cost more, and if you are looking for efficiency, you would want to consider other factors too. The location and purpose of your project can also play a role in affecting your decision to choose the best material for your specific roofing requirement. Quality roofing materials are efficient in the long run given that they require less repair and maintenance budget. Quality roofs typically come with a longer warranty, providing protection to both builders and building owners against worst unexpected cases. Along with quality materials, you might also want to look for extra coatings, ventings, and insulation as well as accessories that assist with moisture prevention on your roof. 

Liaise with the right roofing company so that they recommend you the quality materials that deliver you the best value.

Also Read: A Complete Guide To Commercial Roof Leaks And The Solution

Accommodate Moisture Protection Practices

Since the major cause of corrosion on commercial roofs is the moisture, you would want to prevent it from reacting with the steel as long as it is up and running. Your commercial roof will ultimately face corrosion if there is negligence and you are unable to accommodate moisture prevention practices even if you have the best quality roofing material. You should keep yourself updated with the operations of various systems that either move water away from the roof surface or prevent moisture build-up that can lead to future moisture exposure. Inspect if there is adequate ventilation, insulation, up to date water-proof roofing materials, proper gutters and downspouts etc regularly to keep your steel structure healthy.

Choose The Right Roofing Partner

Choosing the right construction partner with proven track records is the single most important step you can take to install your roof in a corrosion-proof way. Your roofing partner will take care of your roof installation according to its location, potential environmental risks, and your local building code. They can also make suggestions based on their years of experience and keep you aware of the areas where material choices would lead to corrosion. With the right partner, you get the best value. 

Since your commercial roof is exposed to external elements and harsh conditions, it requires regular care and maintenance if you expect the best service in return. Partnering with the right roofing company also helps you maintain your roof in its best condition in the best possible way for its lifespan. Your roofing partner should not be the one that appears during the installation, gets the job done, and disappears. The right roofing partner should assist you throughout the lifespan of your roof and help you maintain it even after years of installation.

Corrosion Treatment

The best way to treat corrosion on an existing roof is to cover it with a protective coating. The coating creates a barrier between steel and water thereby preventing oxidation in iron. 

Most of the quality roofing materials at present come with a protective coating, but with time they are likely to degrade under the environmental exposure. The coating may not work as effectively with time as commercial roofs have a lifespan of up to 70 years. Regular thorough inspection of your roof with roofing experts will allow you to understand the condition of your roof. Corrosion prone areas like cut edges should be inspected frequently and treated accordingly. 

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