Abstract: A device for applying a vapor retarder film onto purlins on a roofing system has a base with rollers and guides for directing the base across the purlins. The base has a fore end and an aft end with a pair of side members. The base moves across the purlins such that the side members remain in a fixed spaced apart relationship wider than the spacing between the pair of purlins. A vertical member attached to each of the side members provides a means for mounting a web of the vapor retarder film on a roll above the base and the adjacent pair of the spaced apart purlins. Adhesive is dispensed onto the edges of the web and the web is payed out and guided onto the purlin so that the edge of the web having the adhesive is put into adhesive engagement with the top surface of the purlins and the film sealingly spans the interval between the adjacent purlins. By use of. a plurality of these devices acting in parallel, a method of applying the web to the roof purlins is taught.

Abstract: A device for applying a vapor retarder film onto purlins on a roofing system has a base with rollers and guides for directing the base across the purlins. The base has a fore end and an aft end with a pair of side members. The base moves across the purlins such that the side members remain in a fixed spaced apart relationship wider than the spacing between the pair of purlins. A vertical member attached to each of the side members provides a means for mounting a web of the vapor retarder film on a roll above the base and the adjacent pair of the spaced apart purlins. Adhesive is dispensed onto the edges of the web and the web is payed out and guided onto the purlin so that the edge of the web having the adhesive is put into adhesive engagement with the top surface of the purlins and the film sealingly spans the interval between the adjacent purlins. By use of a plurality of these devices acting in parallel, a method of applying the web to the roof purlins is taught.