Cleaning Aged EPDM Rubber Roofing Membrane Material for Patching: Laboratory Investigations and Recommendations

Many U.S. Army installations are replacing old, low-slope built-up roofs using EPDM ethylene-propylene-diene terpolymer as the waterproofing component. EPDMs are nonpolar, relatively inert rubbers, and difficult to bond with adhesive. Unaddressed in prior studies, an important factor affecting seam performance and eventual patch durability is the surface condition of the aged EPDM rubber before bonding. This study assessed the effectiveness of different cleaning methods for preparing aged EPDM membranes for patching, and recommends procedures for use in the field. Effectiveness of the cleaning methods was evaluated using tests of short-term strength and long-term creep rupture in peel. Several surface analytical techniques were also used i.e., scanning electron microscopy, Fourier transform infrared spectroscopy, and contact angle measurement. A section of an aged, ballasted EPDM membrane, sampled from a roof after 10 years in service, was used in the study. Most of the methods evaluated were based on procedures currently used to prepare aged EPDM for patching. It was concluded that aged EPDM can be cleaned adequately for patching, and a simple DMF droplet test may indicate the surface bonding condition accurately. Field evaluation of the DMF droplet test is recommended. ethylene-propylene- diene terpolymer EPDM, rubber, roofing, waterproofing.