Membrane Appl. & Seam Assembly

Membrane application and seaming procedures will vary between Peel and Stick TPO and Fully Adhered TPO or EPDM membrane applications, accordingly, the following installation instructions will be divided into Peel and Stick and Fully Adhered sections.

Fully Adhered TPO or EPDM:

Membrane Application

  1. Beginning at the bottom of the roof slope, install the first membrane panel by unrolling the TPO or EPDM membrane onto the prepared roof substrate parallel to the roof edge with enough sticking over the edge to accommodate your edge detail (reference the appropriate detail on this page if necessary) and allow the membrane to relax for 30 minutes.
  2. Fold sheet back without creasing, so one-half (1/2) of the underside of the sheet is exposed. Be sure the sheet fold is smooth with no wrinkles or buckles.
  3. Stir GenTite bonding adhesive thoroughly. Achieve a uniform mix with no marbling and no sediment on the bottom of the pail. DO NOT THIN.
  4. Apply bonding adhesive to the substrate and the membrane with a 9” medium nap roller, approved spray equipment (spray applied bonding adhesive must be back-rolled) or power roller equipment. The membrane and substrate must have 100% adhesive coverage. Do not apply bonding adhesive to the splice area. Avoid globs or puddles of adhesive.
  5. Allow adhesive to dry to the point that it feels tacky to the touch but does not transfer to a clean, dry finger when you conduct a “push” test. Do not allow to over dry. If the surface dries to the point that it no longer feels tacky, reapply bonding adhesive to both surfaces at the prescribed application rate, and allow to flash-off again to the proper drying condition. NOTE: Do not allow adhesive to come into contact with seaming areas. If contamination occurs, remove any contaminates prior to seaming.
  6. Roll the adhesive-coated membrane onto the adhesive-coated substrate, avoiding wrinkles.
  7. Using a push broom and positive pressure, brush down the adhered half of the sheet to achieve maximum contact.
  8. Fold back the un-adhered half of the sheet without creasing, and repeat bonding procedure.
  9. Apply adjoining sheets in same manner, lapping edges a minimum of 3”.

Any wrinkles created in the splice area (referred to as “Fishmouths” in the instructional installation video must be cut out, laid flat and repaired using GenTite Cover Tape applied according to the repair procedure shown in the instruction video.)

Seaming Procedure (used to join multiple membrane panels together)

  1. Position the top membrane so that it overlaps the bottom membrane by 3”. Mark the bottom membrane ½” out from the edge of the top membrane with a lumber crayon or similar marking device to serve as an alignment guide for the seam tape.
  2. Fold the upper seam area flap of un-adhered membrane back onto the adhered membrane and hold in place with temporary weight placed on the membrane edge (not the fold) – DO NOT CREASE
  3. Stir GenTite Clear Primer thoroughly until no sediment or marbling appears in the pail. Do not thin. Pour Seam Primer into the chemical resistant tray included in the Flashing and Seam Accessory kit.
  4. Assemble the GenTite Scrub Pad & Handle supplied in the Flashing and Seam Accessory kit in preparation for use. Dip the pad into the primer, and allow the pad to saturate with primer. Do not roller or brush apply Seam Primer.
  5. Apply Seam Primer to both seaming areas (top of bottom panel and bottom of top panel) using a back and forth scrubbing motion to achieve a solidly primed surface without streaks or puddles. Do not overwork the primer.
  6. Allow the primer to flash off until it no longer transfers to a clean dry finger.
  7. Unroll GenTite Seam Tape along the line on the bottom membrane for the entire length of the seam.
  8. NOTE: DO NOT REMOVE THE RELEASE PAPER FROM THE SEAM TAPE AT THIS TIME. With the release paper still on the tape, hand roll the entire length of seam tape with the seam roller included in the Flashing and Seam Accessory kit, across the narrow span of the seam tape first and then again along the seam tape length. Do not trap air under the seam tape. Be certain there is good contact between the membrane and the seam tape.
  9. Allow the top membrane to fall freely onto the bottom membrane. Pull the release paper from the tape away from the seam, and achieve sufficient contact by brushing your hand across the top membrane at a right angle.
  10. Hand roll the entire length of seam tape with the seam roller included in the Flashing and Seam Accessory kit, across the narrow span of the seam first and then again along the seam length. Do not trap air under within the seam. Be certain there is good contact between the membrane and the seam tape. Special attention is needed at the factory seam step-downs or wherever a seam spans a surface transition – at these locations turn the roller onto the roller edge to press the membrane and seam tape into the transition.
  11. After the seam has been thoroughly rolled in, apply Seam Primer along both sides of the seam step off creating a primed area 7” to 8” wide centered on the seam edge, using a back and forth scrubbing motion to achieve a solidly primed surface without streaks or puddles. Do not overwork the primer.
  12. As the Seam Primer is flashing off, unroll and position the Cover Tape along the primed seam next and wait for the Seam Primer to flash off until it no longer transfers to a clean dry finger.
  13. With the assistance of a second person, peel the release liner from the bottom of the cover tape for the first 2 – 3 feet of cover tape, and while the second person holds the tape off the deck 5 to 8 feet behind you (in line with the seam being stripped in), apply the exposed adhesive side of the cover tape to the primed membrane centered on the seam edge. Maintain application alignment of the cover tape with the seam edge during application to avoid wrinkles in the cover tape. Smooth the applied cover tape onto the membrane as you progress to establish the initial bond. Continue this process for the length of the seam.
  14. Hand roll the entire length of cover tape with the seam roller included in the Flashing and Seam Accessory kit across the narrow span of the cover tape first and then again along the cover tape length. Do not trap air under the cover tape.
  15. Apply a T-Joint Cover over any seam intersections (see T-Joint Cover detail on this page).
  16. Apply a high profile bead of GenTite Edge Caulk along the edge of the cover tape and along the edges of any T-Joint Covers.

 

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