Best Waterproof Coating for Metal Roofs: Top Picks for Durable Protection
Metal roofs demand coatings that resist weather, rust, and UV exposure while staying flexible enough to withstand temperature shifts. This guide highlights five reliable waterproof coatings that perform well on metal roofs, along with key features to consider, and practical buying tips. Each product below is selected for durability, ease of application, and long-term protection against leaks and corrosion.
| Product | Brand | Coating Type | Key Benefit |
|---|---|---|---|
| Rust-Oleum Elastomeric Roof Coating | Rust-Oleum | Elastomeric roof coating | High reflectivity and weather resistance |
| Liquid Rubber Waterproof Sealant | Liquid Rubber | Liquid rubber membrane | Flexible, long-lasting protection |
| Liquid Rubber MetalSafe Sealant | Liquid Rubber | Metal-safe waterproof coating | Corrosion protection for metal surfaces |
| Liquid Rubber Color Waterproof Sealant | Liquid Rubber | Elastomeric coating | Paintable, versatile surface coverage |
| Gardner-Gibson SBS Roof Coating | Gardner-Gibson | Rubberized SBS asphalt coating | Flexible, durable waterproof seal |
Note: All selections focus on metal roof applications, ease of application, long-term durability, and compatibility with common metal roof profiles. The following sections provide detailed overviews of each product, followed by a practical buying guide to help you compare options based on climate, roof slope, and maintenance needs.
Rust-Oleum 4.75 Gallon Elastomeric Roof Coating
Rust-Oleum Elastomeric Roof Coating is designed for flat and low-slope metal surfaces, offering high initial reflectivity and weather resistance. The coating reduces heat absorption and helps manage roof temperature, contributing to potential cooling energy savings. With an 84% initial reflectivity rating and 74% weathered reflectivity, it provides a bright, durable barrier that resists rain and weather in harsh conditions. Proper surface preparation and multiple coats are recommended to achieve optimal membrane thickness and longevity.
Liquid Rubber Waterproof Sealant – 1 Gallon
The Liquid Rubber DIY Sealant creates a seamless waterproof membrane suitable for flat or metal roofs, foundations, gutters, and other surfaces. It emphasizes superior flexibility with over 950% elongation, enabling movement without cracking. The formula resists UV damage and stays durable under temperature fluctuations. Coverage varies by surface and coat thickness: primarily 60-80 mil membranes on flat/low-slope roofs, or around 30 mil on vertical surfaces with two to three coats. It serves as a robust alternative to traditional tar.
Liquid Rubber MetalSafe Sealant (5 Gallon)
Liquid Rubber MetalSafe Sealant is designed for metal roofing systems and corrosion-prone environments. It dries quickly to form a durable waterproof surface with strong UV stability. The product is suitable for lightly rusted surfaces and is easy to apply with brushes or rollers, with options for spray application using compatible equipment. It offers a practical, long-lasting option for metal roofs exposed to moisture, salt spray, or industrial environments where corrosion resistance matters.
Liquid Rubber Color Waterproof Sealant – 1 Gallon
This color-matched elastomeric coating offers a versatile solution for metal roofs and other surfaces. It creates a flexible, seamless membrane that resists leaks and water damage, with good UV resistance and weatherproofing. The product is suitable for quick application via brush, roller, or sprayer, suitable for both new coatings and maintenance on metal, concrete, and flat roof sections. A light gray option blends well with many roof designs and provides additional reflectivity to help reduce heat absorption.
Gardner-Gibson Rubberized SBS Roof Coating
The Gardner-Gibson SBS Rubberized Roof Coating blends rubber and reinforcing fibers to create a flexible, waterproof seal for asphalt-based and metal roof systems. The product is designed to bridge small gaps and joints while remaining durable under thermal cycling. It’s well-suited for retrofit projects on aging metal roofs where a robust, elastic membrane is needed to prevent leaks and extend roof life.
AMES RESEARCH LABORATORIES MSS1 Maximum Stretch Roof Coating
AMES MSS1 Maximum Stretch is a white elastomeric roof coating with 650% elongation, designed to resist cracking and peeling. Its high reflectivity (88%) helps reduce surface temperatures and cooling costs. The coating adheres well to metal roofs, tar, and rolled surfaces, making it a versatile option for low-slope roof maintenance. It can be brushed, rolled, or sprayed, offering flexibility for various project sizes and skill levels.
Buying Guide: Key Purchase Considerations
- Roof compatibility: Ensure the coating is formulated for metal surfaces and suitable for the roof’s slope, maintenance history, and local climate. Some products perform better on flat roofs, while others handle standing water or rust more effectively.
- Elongation and flexibility: Higher elongation helps the coating accommodate thermal movement and avoid cracking. For metal roofs exposed to temperature swings, look for products with 650% elongation or higher.
- Reflectivity and UV resistance: Light-reflective coatings can reduce cooling loads, particularly in sunny regions. If energy efficiency matters, prioritize high reflectivity values and UV stability.
- Durability and UV stability: UV-resistant formulations extend service life and reduce degradation from sun exposure. Consider products with proven weather resistance for harsh environments.
- Application method: Brushes, rollers, or spray systems are common. Assess whether you plan a DIY project or need professional application, and select coatings that align with your toolset and experience level.
- Coverage rate and coats: Review coverage per gallon and the number of coats required to achieve the desired membrane thickness. Flat surfaces typically require more coats for proper sealing.
- Drying and curing times: Some coatings cure quickly, while others need longer periods before exposure to rain. Plan installation around weather forecasts to avoid washout.
- Maintenance and compatibility: If you anticipate future repairs or color changes, consider coatings that are easy to touch up and compatible with existing sealants or coatings.
In selecting a coating, balance performance metrics such as reflectivity, elongation, and durability with practical factors like cost, available application tools, and the roof’s specific exposure. For metal roofs in coastal or industrial areas, prioritizing corrosion resistance and UV stability can be especially important. The products listed above provide a spectrum of options—from high-reflectivity elastomerics to flexible liquid membranes—enabling a tailored approach to metal roof protection.