Versico vs Carlisle EPDM Seam Defect Repair Procedure

Why this matters

EPDM seams fail at the splice, and Versico and Carlisle, though both Carlisle-family brands with closely parallel systems, ship seam accessories that must be matched to their own membrane and primer to keep the warranty intact and the bond reliable. A field repair that mixes a competing brand's tape, uses the wrong primer, or skips the cleaning and rolling steps produces a splice that looks fine and peels in a season. This procedure walks a defect-driven EPDM seam repair, identifying the defect, removing the failed splice, re-preparing the membrane, and re-splicing with the correct brand-matched seam tape and primer, with the inspection that proves the repair will hold. It is written so the same steps apply to either Versico VersiGard or Carlisle Sure-Seal/Sure-Tough EPDM, with the brand-match call made explicit.

Materials and prep

Confirm the membrane brand and system before sourcing anything; Versico and Carlisle are sister brands but their warranties require their own listed accessories.

• Brand-matched seam products: for Carlisle, Sure-Seal/Sure-Tough EPDM with Carlisle Factory-Applied Tape repair or Carlisle SecurTAPE plus HP-250 Primer; for Versico, VersiGard EPDM with Versico seam tape and Versico EPDM Primer. Do not cross brands within a spliced joint covered by warranty.
• Splice cleaner / weathered membrane cleaner (brand-listed), clean white rags, and a stiff scrub pad.
• Seam roller (steel, 2 inch) and a silicone hand roller; utility knife with hook blade; seam probe; pressure-sensitive tape per the system.
• For chronic-leak seams, lap sealant (Carlisle/Versico Lap Sealant) for the cut edge after splicing.

Prepare the work area: the seam must be dry, the ambient and surface temperature within the primer/tape minimum (typically above 40 F and rising, not falling into dew point), and the roof clear of ponding at the seam.

Step-by-step

1. Identify the defect. Probe the full length of the suspect seam. Mark every open lap, fishmouth, void, or wrinkle-induced channel. Open a short section to read the failure: clean separation (primer/contamination failure), tape that pulled away in a film (cold or unrolled splice), or a wrinkle that bridged the splice.
2. Define the repair length. Extend the repair at least 6 inches beyond each end of the defect into sound, well-bonded splice so you tie into good seam, not back into the failure.
3. Remove the failed splice. Cut out the failed tape or peel back the top sheet within the repair length. Trim any wrinkled or stretched membrane that prevents a flat lay-down. Do not nick the lower sheet.
4. Clean both mating surfaces. Scrub the splice area on both sheets with the brand-listed splice cleaner and clean rags until the rag shows no black residue (the EPDM surface is oxidized and must be cleaned to bond). Change rags frequently; a dirty rag re-deposits contamination. Let it flash off fully.
5. Prime. Apply the brand-matched EPDM primer to both surfaces in a uniform, hazy-tack coat per the manufacturer's coverage. Prime the full splice width. Let the primer dry to a tack (it should not string to a gloved knuckle).
6. Apply the splice tape. Position the brand-matched seam tape on the lower sheet's primed area, release liner up, aligned to the splice line. Lay the top sheet down onto the tape without stretching or wrinkling, then remove the release liner by pulling it out as the sheet seats. Avoid trapping air.
7. Roll the splice. Roll the full seam with a steel seam roller across the seam (perpendicular first, then along) with firm, even pressure. Rolling, not hand pressure, makes the bond; an unrolled tape splice is a future failure.
8. Seal the cut edge. Where the system calls for it, apply lap sealant in a continuous bead along the leading edge of the top sheet, feathered onto the lower membrane.

Inspection and QA

Let the splice reach handling strength per the manufacturer before probing. Then probe the entire repaired length and the tie-ins; the probe must ride over a continuous, closed splice with no skips or fishmouths. Verify the repair extends fully into sound seam at both ends. On a representative or required basis, cut a test coupon from a non-critical extension and peel-test it: a correct EPDM tape splice fails by delaminating the membrane or fully bonding the tape, not by clean release at the tape-to-membrane line. Confirm the cut edge is sealed where required and that no wrinkle bridges the splice. Photograph the completed seam, record temperature and the brand/lot of cleaner, primer, and tape used, and confirm all products were the membrane's matched brand so warranty is preserved.

References

• Carlisle SynTec Sure-Seal/Sure-Tough EPDM Design and Application Guide and seam-splice details (SecurTAPE, HP-250 Primer, Lap Sealant).
• Versico VersiGard EPDM Specifications and Details, seam tape and EPDM primer application.
• ASTM D4637, Standard Specification for EPDM Sheet Used in Single-Ply Roof Membrane; ASTM D1876, T-Peel test for splice evaluation.
• NRCA Roofing Manual: Membrane Roof Systems, EPDM field-splice repair guidance.