EverGuard 1121 Bonding Adhesive is a contact-type bonding adhesive specially designed for bonding TPO single-ply membranes and flashings to various roofing substrates. EverGuard® 1121 Bonding Adhesive is a general purpose rubber-based bonding adhesive for attaching TPO-based single-ply membranes to various substrates, including polyisocyanurate insulation and gypsum-based cover boards.