Large, flexible sheets or membranes are often used in the construction industry as roofing material. These sheets are typically delivered to a construction site in a bundled roll, transferred to the roof, and then unrolled and laid flat. The sheets are then affixed to the building structure by employing varying techniques such as mechanical fastening, ballasting, and/or adhering the membrane to the roof deck or insulation layer. In order to achieve the necessary water repellent properties, the sheets are positioned so that the edges of adjoining sheets overlap. These overlapping portions are secured to one another through a number of methods depending upon the membrane materials and exterior conditions. One approach involves providing adhesives between the overlapping portions and applying pressure to the site, thereby creating a water resistant seal.
Adhesives may be applied at the job site in the form of a tape or solid adhesive strip. This method, however, has drawbacks including the need to prime the area where the tape may be applied. Additionally, applying the tape at the job site can be labor intensive and imprecise. Further, construction debris and dirt can contaminate the tape or membrane, leading to flawed or unsatisfactory tape adhesion. To alleviate these problems and provide a more uniform adhesive application, manufacturers provide membrane with a pre-applied tape. In other words, the tape is applied prior to delivery of the membrane to the job site, often within a factory or other controlled environment where priming and cleaning can be performed more effectively, as well as uniform and standard application of the tape.
The ability to pre-apply or factory apply the tape in a uniform, precise manner is particularly advantageous when a tape selvage edge is desired. A tape selvage edge includes the portion of the adhesive tape that overlaps the membrane edge. In other words, the tape selvage edge extends beyond the edge of the membrane and provides additional adhesive to the sealed areas. Particularly, the tape selvage edge improves water resistance and joint stability in areas where more than two membranes converge in areas known as T-joints. This is accomplished because the additional overlapping tape provides a more gradual gradation to the seal and reduces the opening at the T-joints.
Because it has been found that pre-application of the tapes is desirous, it is additionally important to develop efficient methods of applying the tape prior to shipment to a construction site. Particularly, it is preferable to apply tape to more than one membrane at a time, thereby increasing productivity. One such method entails providing a membrane and applying a tape along a central region of the membrane. The membrane and tape is then cut, thus producing two membranes, each of which having a tape on one side. While these construction methods may achieve greater production speeds and efficiency, some drawbacks remain. For example, cutting the membrane and tape after the tape has been applied results in a flush cut edge without a tape selvage. As a result, these methods do not enable a manufacturer to create the more desirable tape selvage edge.
Thus, because the tape selvage edge is desirable, there is a need for a production method that quickly and efficiently applies adhesive tapes to roofing membranes in a manner that can produce a tape selvage edge.