When Should You Use EPDM and Butyl Sealants?

We hope you gained some new insights from our first blog in this series on the importance of materials compatibility.To get more news about Butyl Mastic Tape, you can visit senpinghz.com official website.

In the near future, we’ll round out these valuable tips with an explanation of how load testing the brackets of your rooftop-mounted ancillaries is key to protecting your exposed-fastened (EF) metal roof.

Today, we are taking a deep dive into another vital topic to preserve your roof’s integrity: the world of proper sealants.
Tip #2: When Should You Use EPDM and Butyl Sealants?
EPDM and butyl sealants are two of the most effective weatherproofing products in the metal roofing industry with decades of proven success. Because mounting accessories involves penetrating through your EF roof, these exceptional sealants are critical to prevent roof leaks not only initially, but over the life of your roof. Let’s look at how you can make the most of these sealants.
How Can You Prevent Leakage and Water Intrusion?
Holes in your roof must be sealed, but externally applied caulking and sealants eventually dry out and crack, causing leakage and corrosion.

What Is EPDM Sealant?

EPDM (ethylene propylene diene monomer) is a smooth, semi-hard, synthetic rubber. You can count on EPDM for high-tensile strength, flexibility, long lifespan, reliability in hot and cold climates and moisture resistance. EPDM is so waterproof, it’s even used as pond liners. A preferred roofing material for more than 40 years, EPDM is a favorite product of the commercial roofing industry.

What Is Butyl Tape Sealant?

Butyl tape sealant (a copolymer of isobutylene with isoprene) is an airtight, watertight adherent rubber establishing an impervious moisture barrier. Isobutylene copolymers have been used in the U.S. low-slope metal roofing industry for more than 50 years thanks to their reputation for excellent performance. Uncured and sticky, butyl remains flexible even in extreme temperatures. One study shows butyl tape is still elastic and pliable after 33 years, and it’s estimated to last 60+ years.
How Can You Extend the Materials’ Lifespan?
As is true for almost anything, specific formulations of these sealant types differ from one manufacturer to another. Their individual formulations are proprietary and create their own “secret sauce.” In other words, they don’t all necessarily perform the same. This makes it imperative to source from a vendor who has a long history of success.
Tighter is not better in this case. When you drive in the screw, seat it, but don’t over-torque it. Otherwise, you could thin and displace the gasket material, reducing its life and effectiveness. The best practice is to utilize a part design featuring a built-in-like “reservoir” to encapsulate the material and help prevent over-compression.
Is your roof in the U.S. or abroad? Interestingly, geographic locations affect mounting preferences. We call it “roof culture,” and it varies. Attaching into the flat of the panel (the low valley of your corrugation or flat area between trapezoidal ribs) is commonplace in the U.S. thanks to time-tested waterproofing sealants. For installers in other roof cultures, the penetration is in the higher point of the profile, away from the drainage plane (into the rib). These differentiators are sometimes called “bottom-fix” and “top-fix.”