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April 16, 2021

Metal Roofing Sealant

Metal roofing sealant is one of the major components that make the roofing solution weathertight. Metal roofing isn’t the only place you’ll see sealants being incorporated. Automotive applications, HVAC systems, windows, doors, and more all integrate some sort of sealant material to protect the product. One common misconception is that sealants are used as binding agents; however, be aware this is not what it’s designed for. Sealants are simply used to keepprecipitation from penetrating into the roofing system, so no moisture can accumulate.

Metal Roofing Sealant Variations

Sealants are one of the key factors that allow metal roofing to last for 40 years or more. Without the proper sealants—who knows how long a metal roof would last! Sealants are important, but remember, the roofing system itself is the star of the show. Sealants are used as a secondary reinforcement to ensure the entire roofing system remains weathertight. Furthermore, there are two types of sealants used for metal roofing—caulk sealant and tape sealant. Let’s dive into the difference between the two.

Types of Metal Roofing Sealant: Caulk

Metal roofing caulk sealant is designed to be used with a caulk gun. Load the gun with a tube of caulk and then pull the trigger to distribute the product. It’s pretty common to find a caulk gun from one home to the next. It’s important to realize that metal roofing caulk is different than other sealants, though. Wagner Metal Supply sells and recommends NCP Solar Seal specifically for metal roofing. NCP Solar Seal is a terpolymer rubber-based sealant that is proven to last for 30 years. Overall, we need to remember that sealants are secondary protection to the metal roofing system. Your roof is there to protect the entirety of your home, and sealants reinforce weathertightness. Now, there are some instances where you should use gun caulking sealant, and there are times you shouldn’t.

  • DO uses gun caulking sealant for:
    • Metal to metal connection where there are no fasteners
    • In between panel seams
    • Around pipe boots
  • DO NOT use gun caulking for:
    • Areas with extreme sun exposure
    • Voids or gaps within the metal

Types of Metal Roofing Sealant: Tape Sealant

The second category of metal roofing sealant is tape sealant. Tape sealants are made from butyl—which is a synthetic rubber composed of isobutylene and isoprene. This sealant is typically referred to as butyl tape. Butyl tape certainly has its benefits. This sealant will not harden, stain, or bleed. It’s super simple to install, and it will work for various roofing applications. Butyl tape works at its finest under compression. For example, take your metal panel, a layer of butyl tape, and a Z closure. As you fasten the Z closure to the metal panel, it creates compression on the tape between the two materials. The compression of the butyl tape is what creates the weathertight seal.

  • DO use tape sealant for:
    • Z closures
    • Offset cleats
    • The bottom of pipe boots where it gets attached to the panel
  • DO NOT use tape sealant when:
    • There is no form of compression between two materials

Questions:

There are two main types of sealants used for metal roofing—caulk sealants and tape sealants. Wagner Metal Supply sells and recommends NCP Solar Seal specifically for metal roofing. NCP Solar Seal is a terpolymer rubber-based sealant that is proven to last for 30 years. Tape sealants are made from butyl—which is a synthetic rubber composed of isobutylene and isoprene. This sealant is typically referred to as butyl tape.
There are some instances where you should use gun caulking sealant, and there are times you shouldn’t. You should use gun caulking sealant for metal to metal connection where there are no fasteners, in between panel seams, and around pipe boots.
Butyl tape works at its finest under compression. For example, take your metal panel, a layer of butyl tape, and a Z closure. As you fasten the Z closure to the metal panel, it creates compression on the tape between the two materials. The compression of the butyl tape is what creates the weathertight seal. It’s best used on Z closures, offset cleats, or the bottom of the pipe boot where it attaches to the metal panel.
Wagner Metal Supply carries all the materials needed for your metal roofing project—including metal roofing accessories. You can purchase NCP Solar Seal caulk and butyl tape from the Wagner Metal Supply online store, along with any other metal roofing materials you need.