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  • Writer's pictureScott G.

The Best Sealants to Use on a Metal Roof: A Guide by Bham Roofs

Updated: Jun 19

Metal roofs are a popular choice for their durability, energy efficiency, and sleek appearance. However, to ensure they provide long-lasting protection, it's crucial to use the right sealants. Sealants play a vital role in preventing leaks, corrosion, and other forms of damage. In this blog post, Bham Roofs explores the best sealants for metal roofs, discussing their strengths, weaknesses, and relevant building codes.

Types of Sealants for Metal Roofs

  1. Polyurethane Sealants Strengths: Weaknesses:

  • Flexibility: Polyurethane sealants remain flexible after curing, making them ideal for metal roofs that experience temperature fluctuations.

  • Strong Adhesion: They bond well with metal surfaces, ensuring a tight seal.

  • Durability: Resistant to weathering and UV rays, they offer long-lasting protection.

  1. Silicone Sealants Strengths: Weaknesses:

  • Weather Resistance: Silicone sealants are highly resistant to extreme weather conditions and UV rays.

  • Longevity: They maintain their integrity for a long time, even under harsh conditions.

  • Flexibility: Excellent flexibility allows them to expand and contract with the metal.

  1. Butyl Rubber Sealants Strengths: Weaknesses:

  • Adhesion: Exceptional adhesion to metal surfaces.

  • Water Resistance: Highly effective at preventing water infiltration.

  • Ease of Application: Easy to apply and clean up.

  1. Acrylic Sealants Strengths: Weaknesses:

  • UV Resistance: Excellent resistance to UV rays, making them suitable for sunny climates.

  • Paintability: Can be painted over to match the roof color.

  • Cost-Effective: Generally more affordable than other sealant types.

Understanding Building Codes

When applying sealants to a metal roof, it's important to comply with local building codes and standards. These codes ensure that the materials and methods used provide adequate protection and safety. For example, in Alabama, building codes require:

  • Weatherproofing Standards: Sealants must meet specific standards for weatherproofing to prevent water infiltration.

  • Fire Resistance: Sealants should not compromise the fire resistance of the roof.

  • Environmental Compliance: Use sealants that are environmentally friendly and comply with regulations regarding volatile organic compounds (VOCs).

Before starting any roofing project, always check with local building authorities to ensure compliance with the latest codes and standards.

Here are some of our favorite sealants for metal roofing


Overview: Geocel is a reputable brand offering a range of high-quality sealants specifically designed for construction and roofing applications. Known for their reliability and versatility, Geocel products are widely used in the industry.

Popular Product:

  • Geocel 2300 Construction Tripolymer Sealant

Features and Uses:

  • Superior Adhesion: Bonds well to a variety of surfaces including metal, wood, asphalt, and masonry.

  • Weather Resistance: Excellent durability against UV rays and harsh weather conditions.

  • Flexibility: Remains flexible after curing, accommodating expansion and contraction.

  • Paintable: Can be painted once cured, allowing for a seamless look.

  • Waterproof: Provides a watertight seal, ideal for preventing leaks in roofing applications.


  • Metal roof seams and joints

  • Flashings and gutters

  • Skylights and vents

  • Roof penetrations and HVAC units


Overview: NP100 is a high-performance sealant from Pecora Corporation, designed for demanding construction and industrial applications. It's known for its exceptional durability and flexibility.

Popular Product:

  • Pecora NP100 Polyurethane Sealant

Features and Uses:

  • High Performance: Formulated to deliver strong adhesion and flexibility in a wide range of temperatures.

  • Durability: Resistant to UV radiation, weathering, and aging, ensuring long-lasting performance.

  • Elasticity: Excellent elasticity to accommodate building movement without cracking.

  • Versatile Application: Suitable for both vertical and horizontal surfaces.


  • Metal roofing and siding

  • Expansion and control joints

  • Flashing and gutters

  • Parapets and wall joints

  • Around windows and doors in metal structures


Both Geocel and NP100 offer superior solutions for sealing metal roofs, each with their unique strengths. Geocel 2300 is an excellent choice for those needing a versatile, paintable sealant with strong adhesion to various materials. NP100, on the other hand, excels in providing durable, flexible seals for high-stress applications. When choosing a sealant, consider the specific needs of your project to ensure the best performance and longevity.


Choosing the right sealant for your metal roof is crucial for its longevity and performance. Polyurethane, silicone, butyl rubber, and acrylic sealants each have their unique strengths and weaknesses, making them suitable for different situations. By understanding these differences and adhering to building codes, you can ensure your metal roof remains in excellent condition for years to come. At Birmingham Roofs, we are committed to providing expert advice and top-quality roofing solutions. Contact us today to learn more about our services and how we can help protect your home or business with the best sealants and roofing practices.


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