EPDM Seam Tape Guide: Preparation and Application for a Stronger Seam
Part 2 of our five-part Big Rock University series with H.B. Fuller
A properly prepared surface sets the tone for successful seam tape application. Next, understand how preparation, placement, and installation work together to join two EPDM membrane sheets.
In part two of our Big Rock University series, Blake Lichthardt, Sales Professional for H.B. Fuller, demonstrates EPDM seam tape installation on a membrane mockup. Through a close-up look at the process, Blake explains the details that matter as the seam comes together.
Our first installment, EPDM Primer Guide: Why Unprimed Seams Fail, compared primed and unprimed membrane surfaces to show why a tape’s initial grip does not tell the whole story. This demonstration builds on that lesson, moving from surface preparation to forming a proper seam.
Preparing Both Sides of the Seam
Seam tape fits between overlapping EPDM membrane sheets, so preparation needs to account for both surfaces that will meet.
Blake begins by explaining that the membrane must be clean, dry, and free of dirt and debris. With the demonstration sample already cleaned, he applies primer to both mating surfaces.
He also discusses tape width, an important detail to confirm before installation begins. The tape shown in the demonstration illustrates the process, while the required width and overlap dimensions for an actual roof depend on the specified roofing system.
These early steps establish the conditions for the application that follows. Before positioning the tape, installers must confirm both surfaces are prepared and that the materials and dimensions match the system requirements.
Giving Primer Time to Flash Off
As we explored in part one, applying primer also requires understanding when it is ready to receive tape.
Blake explains that flashing off allows solvents to leave the primer. Covering it too soon can interfere with application and cause problems such as bubbles.
The required time varies with environmental conditions, so readiness is more useful than a fixed waiting period. A clock alone cannot confirm that the primer is dry. Follow the current product instructions for the readiness criteria of the primer being used.
Positioning the Tape and Pulling the Liner
Once the prepared surfaces are ready, Blake positions the two-sided seam tape and brings the upper membrane sheet into place.
The close-up demonstration gives viewers a clear look at the release liner and its role during installation. Blake pulls the liner at an angle, progressively exposing the adhesive as the overlapping membrane contacts the tape.
Seeing this movement makes the sequence easier to understand: tape placement, membrane alignment, and liner removal each play a part in how the seam forms. The demonstration then shows rolling the seam to press the assembly together.
For field installation, use the current roof-system instructions for the required dimensions, rolling procedure, and inspection criteria.
A Step-By-Step Visual Guide:
Putting the Process Together
This installment connects the preparation discussed in part one with the steps involved in forming an EPDM seam. It also offers a useful starting point for crew discussions about preparing both mating surfaces, checking primer readiness, maintaining alignment, and completing the required rolling.
Watch the full Big Rock University video to see Blake carry out the sequence on the mockup and explain the details along the way.
Continue Learning with Big Rock University
Thank you to Blake Lichthardt and H.B. Fuller for continuing to share their knowledge with our customers. Through Big Rock University, we’re connecting product information with practical demonstrations that show how application steps work together and why they matter.
Stay connected as we share the remaining installments in this five-part series. You can also explore H.B. Fuller roofing solutions at Big Rock Supply or reach out to our team with questions about the products featured.