Tests of Adhesive-Bonded Seams of Single-Ply Rubber Membranes

Commercially-available ethylene propylene diene terpolymer (EPDM), neoprene, and chlorosulphonated polyethylene (CSME) roofing membrane specimens with adhesive-bonded seams were tested in tension in a lap-shear configuration. Some T-peel tests of an EPDM material were also conducted. The lap-shear tests were conducted at temperatures ranging from −20 to 75°C (−4 to 167°F), and at rates of loading from 0.05 to 50 cm/min (0.02 to 20 in./min). In most cases, the EPDM and neoprene specimens failed by seam delamination; otherwise, they failed by membrane rupture with partial delamination of the seam. The CSME specimens always failed by membrane rupture without seam delamination. In general, the results indicated that, as the temperature of the test increased, the ultimate load and elongation at failure decreased. Also, at a given temperature, the ultimate load and elongation generally decreased, for most specimens, as the rate of loading decreased. For stress relaxation experiments, specimens strained to 15% remained intact for over 15 months, whereas other specimens strained to 30% failed in about five weeks. The results of the tests are discussed with regard to the development of tests for seams in single-ply membranes.