Abstract: Embodiments disclosed herein provide a novel and cost effective application of a thermoplastic heat-welding rod for welding thermoplastic standing seam profiles and other similar materials to thermoplastic roofing membrane, and providing secure attachment without roof penetration and profile/membrane separation. In addition, embodiments disclosed herein provide a welding attachment or apparatus for performing such heat-welding of thermoplastic materials. In one embodiment, an apparatus for welding a thermoplastic profile strip to a thermoplastic membrane may comprise a first nozzle configured to direct hot air along a portion of a first longitudinal edge of a horizontal base of a thermoplastic profile strip placed on a thermoplastic membrane. Also, such an apparatus may comprise a second nozzle configured to direct hot air along a portion of a second, opposing longitudinal edge of the thermoplastic profile strip.