The use of counter flashing, although often overlooked, is one of the most important parts of completing any roofing system. This flashing should be used in conjunction with base and step flashing, to help form a waterproof barrier.
Where to use Counter Flashing
Counter flashing is required at any point where a vertical masonry wall meets any type of roofing surface. This scenario applies to both chimneys and exterior walls on split level and other similarly designed homes. Counter flashing should also be used when roofing meets a vinyl exterior wall surface. In these cases, the vinyl siding acts as the counter flashing and the use of metal flashing material is not required.
When to use Counter Flashing
Counter flashing should be installed after the base and step flashing have been installed, between the roofing material and the exterior wall. The base flashing is installed first followed by interlaying the step flashing between each layer of shingles. The counter flashing is then cut into the masonry joint along the edge, and bent over the step flashing. The combination of all 3 flashing and roofing systems are designed to direct the flow of water away from the inside of your home.