What is Urethane Roofing? (Types, Coating Systems, and How They Work)

Have you ever wondered what urethane roofing is? If so, you’re in luck! We’re going to cover the basics of urethane roofing, including its types, coating systems, and how they work.

Table of contents

What is urethane roofing?

Urethane roofing, also known as polyurethane roofing, is a type of roofing system that is made from polyurethane, a synthetic material composed of organic polymers. Urethane roofing is known for its durability, flexibility, and resistance to various environmental conditions, making it suitable for both residential and commercial applications.

Urethane roofing is typically installed as a spray-applied foam that expands and forms a seamless, monolithic layer on the roof surface. The foam adheres to the substrate, creating a seamless, watertight barrier that can protect the underlying roof structure from leaks, weather damage, and UV radiation.

Urethane roofing is commonly used on flat or low-slope roofs and can be applied over a variety of substrates, including metal, concrete, wood, and existing roofing materials. It can also be used in roof insulation applications to improve energy efficiency by reducing heat transfer through the roof.

One of the advantages of urethane roofing is its versatility, as it can be customized to meet specific requirements, such as varying thicknesses, slopes, and drainage requirements. It is also known for its high tensile strength, which allows it to withstand foot traffic, hail, and other impacts without easily cracking or puncturing.

Due to the specialized equipment and knowledge needed, professional contractors who have received proper application training typically install urethane roofing. Regular maintenance and inspections are important to ensure the longevity and performance of urethane roofing systems.

What are the types of urethane roofing systems?

Aliphatic urethane roofing

Aliphatic urethane roofing systems are known for their excellent UV resistance and color retention properties.

They are formulated with aliphatic polyurethane, which is more resistant to UV radiation than aromatic polyurethane.

As a result, aliphatic urethane roofs tend to maintain their color and appearance better over time, without yellowing or chalking.

This makes them ideal for roofs that are exposed to direct sunlight for extended periods, as they can resist fading and deterioration caused by UV radiation.

Aliphatic urethane roofing systems are often used in commercial and industrial applications where aesthetics and long-term performance are important.

Aromatic urethane roofing

Aromatic urethane roofing systems, on the other hand, are formulated with aromatic polyurethane, which is less expensive but not as UV resistant as aliphatic polyurethane.

Aromatic urethane roofs are typically black or dark in color, and they may experience some color fading and chalking over time when exposed to sunlight.

However, they are still durable and offer good performance in terms of waterproofing and weather resistance.

Aromatic urethane roofing systems are commonly used in commercial and industrial applications where UV resistance and color retention are not a primary concern, and cost-effectiveness is a consideration.

Benefits of using urethane roofing

Seamless and watertight: Urethane roofing is installed as a spray foam that forms a seamless and monolithic membrane when applied. This eliminates the need for seams or joints, which are common sources of leaks in traditional roofing systems. The seamless nature of urethane roofing provides an effective barrier against water infiltration, making it highly waterproof and reducing the risk of leaks.
Excellent insulation: Urethane roofing has outstanding insulation properties, which can help improve energy efficiency and reduce heating and cooling costs. The foam provides a continuous layer of insulation with a high R-value (thermal resistance), helping to keep the building interior comfortable year-round and reducing the reliance on heating and cooling systems.
Versatile application: Urethane roofing can be applied to various types of roofs, including flat or low-slope roofs, as well as roofs with irregular shapes or contours. The foam can conform to different roof surfaces and can be applied to a wide range of substrates, including metal, concrete, wood, and more, making it a versatile option for different roofing needs.

Durable and long-lasting: Urethane roofing is known for its durability and longevity. The cured foam forms a tough and flexible membrane that can withstand various environmental conditions, such as temperature changes, UV radiation, and moisture, without cracking or deteriorating. Urethane roofing is also resistant to many chemicals, making it suitable for use in industrial or corrosive environments.
Lightweight: Urethane roofing is relatively lightweight compared to traditional roofing systems, which can help reduce the overall load on the building structure. This can be beneficial for both new construction and roof replacement projects, as it can potentially reduce the need for additional structural support and lower construction costs.
Seamless repairs: In the event of damage or wear, urethane roofing can be easily repaired with additional foam application. The seamless nature of the foam allows for seamless repairs, without the need for extensive patching or reseaming, making it a cost-effective and efficient option for maintenance and repairs.

Sustainability: Urethane roofing is considered environmentally friendly as it is energy-efficient and can be applied over existing roofing systems, reducing the need for tear-offs and landfill waste. Additionally, some urethane roofing systems are formulated with low volatile organic compounds (VOCs), contributing to better indoor air quality.
Customizable: Urethane roofing systems can be customized to meet specific project requirements, including thickness, insulation levels, and additional coatings or layers. This allows for flexibility in design and performance, making it suitable for a wide range of roofing applications.

What are the drawbacks of urethane roofing?

Cost: Urethane roofing can be more expensive upfront compared to traditional roofing systems. The cost of materials, equipment, and professional installation can be higher for urethane roofing, which may impact the overall budget of a roofing project.

Complexity of installation: Urethane roofing requires specialized equipment and trained professionals for proper installation. The mixing and application of the two components of urethane foam, typically a polyol component and an isocyanate component, require precise measurements and expertise to ensure proper curing and performance. Improper installation can result in poor adhesion, inadequate insulation, or other issues that may impact the effectiveness of the roofing system.
Environmental conditions: Urethane roofing installation is weather-dependent and may be affected by environmental conditions such as temperature, humidity, and wind. Extreme weather conditions may affect the curing process and performance of the urethane foam, requiring careful planning and coordination during installation.
Maintenance and recoating: Urethane roofing may require periodic maintenance and recoating to maintain its performance and longevity. This may include inspections, repairs, and recoating as needed, which can add to the ongoing maintenance costs of the roofing system.

Limited UV resistance: Urethane foam may not have the same level of UV resistance as some other roofing materials. Over time, prolonged exposure to UV radiation may cause the foam to degrade or discolor, requiring additional protective coatings or maintenance to mitigate potential UV damage.
Limited foot traffic resistance: Urethane roofing may not be as resistant to foot traffic as some other roofing materials. Walking or heavy traffic on the foam surface may cause damage or premature wear, requiring careful consideration of roof access and usage.
Chemical sensitivity: Urethane foam may be sensitive to certain chemicals or solvents, which may impact its performance or longevity. It’s important to consult with the manufacturer’s guidelines and avoid contact with incompatible chemicals or solvents to prevent potential damage to the urethane roofing system.

Compatibility with existing roofing: Urethane roofing may not be compatible with all types of existing roofing systems. Proper surface preparation and compatibility testing may be required to ensure adequate adhesion and performance when applying urethane foam over existing roofs.

How do you install urethane roofing?

Prepping your roof for the foam: We’ll either remove your old roof material or, in many cases of old foam or shingles, simply apply the foam layer over it, sealing it.
Applying the foam: This foam layer is sprayed onto your roof as a liquid. It quickly dries and solidifies, forming a solid, durable, and energy-efficient layer. The foam used is polyurethane foam, a closed-cell, high-density insulation that forms a complete, tight seal against your roof, helping prevent the movement of heat between your attic and the outside, keeping your home cooler in the summer and warmer in the winter.

Applying the coating: Once the foam layer is in place, we’ll apply a high-quality, durable exterior coating over it, known as the elastomeric coating. This coating completely seals the polyurethane foam from the outside and is specially formulated to be waterproof and resist the constant bombardment of UV rays onto your roof.
Quality assurance: After applying the elastomeric coating, we’ll conduct a final quality assurance check to ensure that the roof is completely sealed and protected. This step ensures that the foam roofing system is properly installed and will provide the desired benefits of energy efficiency and durability.

What types of roofing substrates can urethane roofing be used on?

Built-up roofs (BUR): Urethane roofing can be applied over built-up roofs, which are typically composed of multiple layers of asphalt or tar paper.

Metal roofs: Urethane roofing can be applied over metal roofs, including steel, aluminum, and other metal substrates commonly used in commercial and industrial roofing.
Concrete roofs: Urethane roofing can be applied over concrete roofs, which are often found in commercial or industrial buildings.
Spray foam roofs: Urethane roofing can be applied over existing spray foam roofs, providing an additional layer of insulation and protection.

Modified bitumen roofs: Urethane roofing can be applied over modified bitumen roofs, which are made from asphalt-based sheets.
Single-ply roofs: Urethane roofing can be applied over single-ply roofs, such as TPO (thermoplastic olefin), PVC (polyvinyl chloride), or EPDM (ethylene propylene diene terpolymer) roofs.

What kind of waterproofing protection does urethane roofing provide?

Urethane roofing, also known as foam roofing or polyurethane foam roofing, provides effective waterproofing protection for your roof.

One of the main ways urethane roofing achieves waterproofing is through the application of a durable elastomeric coating over the polyurethane foam layer. This coating is specially formulated to be waterproof and resistant to UV rays, weathering, and other environmental factors.

Urethane roofing creates a seamless, monolithic layer without any seams, joints, or fasteners. This eliminates potential points of water penetration, providing a continuous barrier against water intrusion.

Also, urethane roofing can be sprayed around roof penetrations such as vents, pipes, and HVAC units, creating a self-flashing seal around these areas. This helps to prevent water from infiltrating through gaps or cracks around these penetrations, reducing the risk of leaks.

Furthermore, urethane roofing is designed to resist ponding water, which is standing water that may occur on flat or low-slope roofs.

The closed-cell structure of the polyurethane foam and the elastomeric coating provide protection against water penetration, even in areas of prolonged standing water.

Overall, urethane roofing is highly flexible and can accommodate the natural movement and settling of the building without cracking or splitting, which helps to maintain its waterproofing integrity over time.

How much does it cost to coat a roof with urethane?

The cost of coating a roof with urethane can vary depending on various factors, such as the size of the roof, the type of urethane used, the location, and the complexity of the project.

Actual estimates for urethane roof coatings can range from $4 to $8 per square foot, with silicone and acrylic coatings falling in a similar price range.

How long does urethane roofing last?

Urethane roofing, like any roofing system, can have varying lifespans depending on various factors such as maintenance, climate, the thickness of the foam coating, and overall roof condition.

On average, urethane roofing is expected to last around 20 years. However, with proper maintenance and favorable conditions, it can last longer.

How to repair damaged urethane roofs

Step 1: Gather materials and tools

You will need the following materials and tools for the repair:

Pot-fill adhesive sealant: This is a PVC-type material in a putty form that is used for patching holes in foam roofs.

Polyester fabric mesh: Look for a durable mesh fabric, such as the Tight Tex brand, that is resistant to tearing.
Additional coat of adhesive sealant: You will need some extra adhesive sealant to apply over the mesh fabric.

Step 2: Clean and prepare the damaged area

Ensure that the damaged area of the urethane roof is clean and free from debris. Use a brush or cloth to remove any loose material or dirt around the hole.

Step 3: Fill the hole with adhesive sealant

Apply a small amount of the pot-fill adhesive sealant to fill the hole in the foam roof. Use a putty knife or similar tool to spread the sealant evenly and fill the hole completely. Smooth out the surface of the sealant to make it level with the surrounding foam.

Step 4: Apply polyester fabric mesh

Cut a piece of polyester fabric mesh slightly larger than the size of the repaired hole. Place the mesh over the filled hole, ensuring that it covers the entire area and extends beyond the edges of the hole. Press the mesh firmly onto the adhesive sealant to embed it.

Step 5: Apply another coat of adhesive sealant

Apply another coat of adhesive sealant over the polyester fabric mesh, using a putty knife or similar tool. Be generous with the sealant, but avoid creating a large mound of sealant over the mesh. Smooth out the surface of the sealant to create an even and clean finish.

Step 6: Allow the repair to dry and cure

Allow the repaired area to dry and cure according to the manufacturer’s instructions for the adhesive sealant. This may typically take a few hours or overnight, depending on the specific product used.

Does urethane roofing come with a warranty?

Urethane roofing coatings typically come with a warranty that ranges from 5 to 10 years, depending on the type of coating you purchase.

The specific terms and length of the warranty may vary depending on the manufacturer and product.

The warranty typically covers defects in materials and workmanship and may also include protection against premature failure, cracking, peeling, and other issues related to the performance of the urethane roofing coating.

Alternatives to urethane roofing

Silicone roof coatings

Silicone coatings are liquid-applied roofing materials known for their excellent UV resistance and flexibility.

They are applied in multiple layers and can be used on various substrates.

Pros include high UV resistance and flexibility, but cons include a higher cost and the potential need for additional surface preparation.

Acrylic roof coatings

Acrylic coatings are easy to apply and dry to a hard, durable finish.

They are typically used in mild to moderate weather conditions and can be budget-friendly.

Pros include easy application and durability, but cons include potential lower resistance to extreme weather and more frequent re-coating.

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