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 . furthermore , the apparatus may also comprise a tubular splitter configured to simultaneously supply hot air to the first nozzle and the second nozzle .