Metal roofs are a popular choice for both residential and commercial buildings due to their durability, energy efficiency, and resistance to rust and corrosion. However, over time, these roofs can develop issues that may compromise their performance and longevity. 

To combat these problems and give your metal roof a new lease on life, applying a suitable roof coating is essential. With numerous options available on the market, choosing the right coating can be a daunting task. 

Understanding the Common Problems with Metal Roofs

Metal roofs are prone to certain issues that can affect their performance and structural integrity. Some of the most common problems include thermal expansion and contraction, rust formation, corrosion, leaks, and loss of energy efficiency. Thermal expansion occurs when metal roofs are exposed to extreme temperature fluctuations, leading to nail pops and gaps that allow water to seep through. Rust and corrosion are natural processes that can weaken the metal and compromise its protective coating. Leaks can occur due to compromised seams or loose fasteners, while loss of energy efficiency is a result of the roof’s reflective properties diminishing over time. Coating your metal roof can address these problems and provide long-lasting protection.

Types of Metal Roof Coatings

When it comes to metal roof coatings, there are several options available, each with its own unique properties and benefits. Understanding these options will help you make an informed decision when choosing the best coating for your metal roof.

Acrylic Coatings

Acrylic coatings are a popular choice for metal roofs due to their flexibility, durability, and energy efficiency. These coatings are made of polymer-based materials that provide excellent UV protection and resist rust and corrosion. Acrylic coatings can fill gaps and cracks, increasing the roof’s energy efficiency and preventing water leaks. They are easy to apply and dry quickly, making them a convenient option for both residential and commercial metal roofs.

Silicone Coatings

Silicone coatings are highly recommended for metal roofs exposed to harsh weather conditions. These coatings offer superior waterproofing properties and protect against UV radiation, heat, and moisture. They can withstand extreme temperature fluctuations and expand and contract with the metal, ensuring long-lasting performance. Silicone coatings are commonly used in commercial roofing applications due to their durability and ability to extend the roof’s lifespan. They are easy to install and require minimal maintenance, making them a cost-effective choice in the long run.

Polyurethane Coatings

Polyurethane coatings are known for their exceptional impact resistance and ability to withstand foot traffic. They provide excellent protection against abrasion, impact, and harsh environmental conditions. Polyurethane coatings come in two types: aromatic and aliphatic. The aromatic base coat is durable but lacks UV resistance, while the aliphatic topcoat offers UV stability and color retention. This combination provides a long-lasting and aesthetically pleasing finish for metal roofs.

Asphaltic Rubber Membrane Systems

Asphaltic rubber membrane systems are an innovative solution for extending the life of existing metal roofs. These cold-process fluid-applied materials form a fully adhered, seamless rubber membrane that provides instant waterproofing and weatherproofing capabilities. They combine the elastic properties of rubber with the waterproofing characteristics of asphalt, creating a durable and cost-effective roof coating system. Asphaltic rubber membrane systems are suitable for both commercial and industrial metal roofs and can be applied to various thicknesses to meet specific requirements.

Properties to Consider When Choosing a Metal Roof Coating

When selecting a metal roof coating, several key properties should be taken into consideration. These properties will ensure that the coating provides optimal protection and longevity for your metal roof.


Durability is a crucial factor to consider when choosing a metal roof coating. Metal roofs are designed to withstand harsh weather conditions, but the coating should provide an additional layer of protection. Look for coatings that are specifically formulated to withstand UV radiation, thermal expansion and contraction, and impact. A durable coating will ensure that your metal roof remains in excellent condition for years to come.

Corrosion Resistance

Metal roofs are susceptible to corrosion and rust, especially in areas with high humidity or exposure to saltwater. To prevent these issues, choose a coating with excellent corrosion resistance. A high-quality coating will create a barrier that prevents moisture from reaching the metal surface, reducing the risk of corrosion and rust formation.


Waterproofing is essential for metal roofs, as water penetration can lead to leaks and structural damage. Ensure that the coating you choose has excellent waterproofing properties and can withstand ponding water. A waterproof coating will protect your metal roof from the adverse effects of water, such as rust, corrosion, and deterioration.

UV Resistance

Metal roofs, despite their reflective properties, can still be affected by UV radiation. Over time, UV rays can cause the metal to degrade and lose its protective coating. Therefore, it’s important to select a coating that offers exceptional UV resistance. A UV-resistant coating will prevent the metal roof from fading, cracking, and deteriorating due to prolonged sun exposure.


Metal roofs undergo thermal expansion and contraction as they are exposed to temperature fluctuations. This movement can cause nails to pop up and create gaps for water to seep through. To prevent these issues, choose a coating that has excellent flexibility and can accommodate the metal roof’s movement. Elastomeric coatings are particularly well-suited for this purpose, as they can expand and contract with the metal, keeping it securely fastened to the roof deck.


Proper adhesion is crucial for the effectiveness of a metal roof coating. Look for coatings that have been tested and proven to adhere well to metal surfaces. This ensures that the coating forms a strong bond with the roof, providing long-lasting protection. Allow the coating to dry for the recommended time to ensure optimal adhesion.

Low Maintenance

Choosing a metal roof coating that requires minimal maintenance can save you time and money in the long run. Look for coatings that are resistant to dirt, debris, and mold growth, as these factors can affect the roof’s performance and aesthetics. A low-maintenance coating will reduce the overall cost of maintaining your metal roof and extend its lifespan.

Factors to Consider When Choosing a Metal Roof Coating

In addition to the properties mentioned above, several factors should be considered when selecting a metal roof coating. These factors will help you make an informed decision based on your specific needs and circumstances.

Type of Metal Roof

The type of metal roof you have will determine the best coating option for your specific application. Different types of metal roofs may require different coatings, so it’s important to choose one that is compatible with your roof material. Consider the lifespan of your roof and select a coating that will provide optimal protection for its expected lifespan.

Climate and Weather Conditions

The climate and weather conditions in your area play a significant role in the performance of a metal roof coating. If your roof is exposed to extreme weather conditions such as heavy rain, snow, or high winds, choose a coating that offers superior water resistance, durability, and UV resistance. Consider the average temperature and humidity levels in your region to ensure that the coating can withstand the local climate.

Application Method

The application method of a metal roof coating can vary depending on the type of coating being used. Some coatings can be applied using a spray gun, while others may require a roller or brush. Follow the manufacturer’s instructions for the specific coating to ensure proper application. If you are unsure about the application process, it is advisable to hire a professional roofing contractor to ensure the coating is applied correctly.


The cost of applying a metal roof coating can vary depending on various factors, such as the size of the roof, the type of coating, and labour costs. Consider your budget and obtain quotes from reputable roofing contractors to get an accurate estimate of the overall cost. Remember that investing in a high-quality coating may have long-term cost benefits by reducing maintenance and extending the lifespan of your metal roof.

How to Apply Metal Roof Coatings

Applying a metal roof coating requires proper preparation and application techniques to ensure optimal performance and longevity. Follow these steps to ensure a successful coating application:

Step 1: Surface Preparation

Before applying any coating, ensure that the metal roof surface is clean and dry. Remove any dirt, debris, rust, or loose paint using a wire brush or pressure washer. Repair any damaged areas and ensure that the roof is free from leaks. It’s important to follow the manufacturer’s requirements for surface preparation to ensure proper adhesion of the coating.

Step 2: Application Techniques

The specific application technique will depend on the type of coating being used. Read and follow the manufacturer’s instructions carefully to ensure proper application. Some coatings can be sprayed on, while others may require a roller or brush. Apply the coating evenly and ensure that it covers the entire roof surface. Allow the coating to dry for the recommended time before exposing it to weather conditions.

Step 3: Safety Considerations

When applying metal roof coatings, always prioritise safety. Wear appropriate protective gear, such as gloves, safety glasses, and a respirator, to protect yourself from chemicals and fumes. Work on the roof in safe conditions, avoiding slippery surfaces or adverse weather conditions that could compromise your safety.

Step 4: Professional Assistance

If you are unsure about the application process or lack the necessary expertise, it is recommended to hire a professional roofing contractor. They have the knowledge and experience to apply the coating correctly, ensuring optimal performance and longevity. Professional installation may also be required to qualify for warranty coverage from the coating manufacturer.


Metal roof coatings provide an effective and cost-efficient solution to protect and enhance the performance of metal roofs. By choosing the right coating for your specific needs, you can extend the life of your metal roof, prevent leaks, reduce energy consumption, and enhance its overall appearance. Consider the properties and factors discussed in this guide to make an informed decision when selecting a metal roof coating. Proper application and regular maintenance will ensure that your metal roof remains in excellent condition for years to come.

For reliable and professional roofing services in Sydney, contact Sydney Roofing Co. We connect homeowners and businesses with trusted roofing service providers in the Sydney area. Whether you need a new roof installation, roof repairs, or metal roof coating, our network of contractors is ready to assist you. Contact us today to schedule a free roof inspection and consultation.