waterproofing metal roof

Waterproofing Metal Roof: 4 Tips From a Professional Roofer

Metal roofs are prone to corrosion or rust, which can lead to leaking and unwanted repair. Waterproofing metal roof coatings is one way to protect your building, especially if you’re in an area that gets rained often.

If you’re a commercial building owner, keeping your roof durable enough is a must to keep your operations running smoothly all year round.

As a professional roofer with over 25 years of experience, I have gathered the most important waterproofing tips for your metal roofs. These tips are critical for you to know especially if you have an upcoming waterproofing project for your metal roof. Let’s get started!

Common Problems Affecting Metal Roofs

Metal roofing can be an especially challenging surface to work on. While metal can offer a reliable roofing solution, leaks often occur from compromised seams or loose fasteners caused by natural expansions and contractions of the structure. Another frequent issue for commercial metal roofs is corrosion – both corrosion and rust involve chemical processes that lead to material disintegration.

Waterproofing Metal Roofs: What’s In It For You?

Before we dig into the tips for efficiently waterproofing your metal roof, let’s discuss first the major benefits that a commercial building owner can get from installing metal roofs:

Energy efficiency: 

A metal roof coating is highly reflective and has excellent UV stability. Waterproof coatings bounce the sun’s radiation back, and away from the building. This can avoid hot temperatures inside the building, so you can save money on high electricity bills.

Provides adequate protection to the entire building: 

A roof coating system can efficiently protect a building from water damage. This prevents further damage to the building’s interior structure.

Reduced maintenance costs: 

Metal roofs are prone to rust. But since the entire roof surface is covered with a waterproof roof coating, it gives the metal roofs more durability and strength. This prevents any hefty and tedious repairs and maintenance costs.

[Read More: 5 Benefits Of Metal Roofing For Commercial Buildings]

Best Tips for Waterproofing Metal Roof Coatings

roofer waterproofing metal roof

1. Always Check the Surface

Before the start of your roof coating project, it is always important to start with the surface. Clean off the entire surface with denatured alcohol, acetone, and lacquer thinner, and avoid using soap when cleaning the metal roof off. Soap can reduce the adhesion properties of the waterproof coating that you will use.

Additionally, you also have to check the current condition of your metal roof. If you notice that there are loose fasteners or rusted metal sheets, focus on repairing them first before applying the roof coating. You may use liquid rubber seam tape to seal the joints and seams of your metal roofing.

2. Remove Existing Waterproofing

rusty metal roof

Not a lot of people know that previous coatings of waterproofing membranes should be removed before applying another coating on your metal roof. Your existing roof coating has to be removed through a chemical application or by physically scraping off the old coating.

3. Use Appropriate Roof Coating Sealant

waterproofing metal roof

One good thing about metal roofs is that they are made not to allow fluid to pass through, but you still have to take care of the edges, seams, joints, and contact points of your building structure. Sealants should be applied to these areas to prevent moisture and water from getting into the roofing system. 

There are currently two basic categories of metal roof sealants that you can choose as a property owner: 

  • Solvent-based: This type of sealant is highly resilient to harsh environmental elements, and has a thicker texture. It is also more expensive, and the application needs a professional-grade aspirator due to the toxic fumes that it emits.
  • Water-based: This sealant is less expensive than solvent-based ones and it doesn’t emit harmful fumes during application. However, it is less resistant to harsh weather conditions and may need additional coatings every few years. 
  • Liquid Rubber: This is a type of synthetic rubber that can be applied as a liquid and then cured to form a flexible, durable, and waterproof membrane. It is typically made from a combination of natural and synthetic rubber, along with various additives to improve its properties.
  • Silicone sealants: This sealant is made from silicone polymer, which is a synthetic material that is both heat and chemical resistant. 

[Related: Top 3 Commercial Roof Waterproofing Materials]

4. Invest in Underlayment

A roofing underlayment is considered the second layer of protection for your roof, but not all underlayments are created equal. You can either use synthetic or felt underlayment for your metal roofings to create a better sealing action against water and moisture.

FAQs About Metal Roof Waterproofing:

roofing contractor

Check out some of the frequently asked questions about metal roof waterproof coatings:

What kind of sealant to use on metal roofs?

We have talked about the two categories of waterproofing sealants for metal roofs, but there are 5 kinds that you can use for your metal roof. They are the following:

  • Acrylic
  • Polyurethane
  • Silicone
  • Liquid Rubber
  • Sealant tape

Can liquid rubber be used on metal?

Yes, a liquid rubber waterproof sealant is solvent-free, non-toxic, and water-based, so it can be applied to generally any type of roof surface, including metal roofs. 

Liquid rubber adheres to all surfaces such as wood, metal, concrete, bricks or stone, fabric, wood, plastics, aluminum, and porcelain.

Does a metal roof need a moisture barrier?

Yes, it is highly recommended to have a moisture barrier on your metal roof. This is essential to prevent condensation and protect against moisture buildup on your roof that can lead to leaking. The buildup of moisture can cause rust and mold buildup that can cause extensive damage to your roof panels.

Get Professional Help for Metal Roof Coating System

metal roof

It is time to stop leaks and invest in highly efficient metal roof coating systems today. These quick tips are indeed helpful for you, but it is always best to have waterproof coatings installed by a professional. 

Easy Roof Solutions can help you with any of your roofing needs. We can have your metal roofs coated with efficient waterproof materials to protect your commercial building from leaks and rust. You can even have the flexibility to get custom colors to match your commercial building.

Give us a call today for a free quote!

About the Author
Kenneth Byler Easy Roof Solutions

Ken Byler

Founder of Easy Roof Solutions, LLC. He started in the construction industry at the age of 14 and has been involved in it for over 25 years. His wide experience in commercial roofing speaks for itself.

Outside his roofing work, Ken enjoys being in the great outdoors, traveling to new places, and bonding with his wife and children.

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