The correct placement of end laps is essential to creating watertight self-adhered roofing systems. Here are some quick tips to keep in mind:
• Make sure all side and end laps are installed with the slope of the roof to ensure that no laps are installed against the flow of water.
• During installation, be aware of end lap placement of the base or interply and cut sheets to length as needed to ensure a 3’ offset.
• The end lap should be 4” for base sheet and interply and 6” for cap sheets.
• Cut the corners of the end lap at an angle, alternating sides between the underlying sheet and the overlapping sheet as shown in the diagram. λ
Joe Thompson is a key member of the CertainTeed Commercial Roofing Technical Services team and leads installer training courses, which are held throughout the U.S. CertainTeed
