There are many styles and configurations of pipe flashings on the market. The more popular versions, like the Dyna-Flash, are made of ethylene propylene diene monomer rubber (EPDM), which permits sleeve flexibility to absorb vibration and pipe movement caused by expansion and contraction, while also providing maximum resistance to weathering due to zone and ultraviolet light.
Problems arise from a roof penetration that isn’t properly flashed
They have a round, flexible metal base that can be molded to conform to most any metal roof panel, which allows for on-site customization. They also come standard in a variety of 14 different colors, all of which carry a minimum 20-year warranty. Multiple configurations can handle numerous applications like sealing a vent pipe that penetrates through a metal roof or terminating a panel where it meets a roof curb. There are countless options available.
Different Flashings
Standard pipe flashings installed/slid over the top of a pipe are manufactured to fit pipes ranging in size from 0.0-inch outside diameter (OD) all the way up to 28 1/2-inch OD and will handle temperatures ranging from -67 F up to +212 F continuous, and intermittent temperatures of +275 F. For example, a #3 Dyna-Flash will fit pipe sizes ranging from 0.25-inch OD up to 5-inch OD. Each flashing is clearly marked with pipe diameters so the flashing can be properly trimmed to fit the penetration. High-temperature silicone flashings are also available in either grey or red, and will handle continuous temperatures up to +437 F, as well as intermittent temperatures up to +500 F. Retrofit flashings are available for applications where the pipe flashing cannot be installed/slid over the pipe.
Retrofit flashings are similar to standard flashings in design but allow you to separate the flashing, wrap it around the penetration and then use an incorporated stainless steel “zipper” to reattach the flashing back together. These retro flashings are available in standard versions and high-temperature silicone as well.
Severe-Slope flashings are another option if needed. These flashings come with a built-in 12:12 pitch allowing the flashing the room needed to accommodate severe roof slopes ranging from 3:12 pitch to 16:12 pitch, and come standard with a square base. All of these flashings are designed to be used on round pipe applications; however, square tube standard and retrofit flashings are available as well.
Other options are two styles of caps to terminate trapezoidal standing seam panels. Also, there are 2-D flashings for round wall penetrations and EPDM roll flashing that has flexible metal sides that can be used for conditions such as parapet walls, stepped roofs or even expansion joints, as well as many other abnormal applications where a standard or retrofit flashing won’t work.
Pipe flashings are very user-friendly and installation is straightforward. First, determine the proper flashing size needed by measuring your penetration OD. Since all flashings have a range of sizes they will accommodate, the best practice is to stay somewhere near the middle of that range. Next, locate the same size OD as your pipe on the flashing and trim to create the proper size opening on your flashing. Slide the flashing over the pipe, unless using a retrofit which is installed around the pipe. If needed, use water to help the flashing slide over the penetration properly.
When installing retrofit flashing, make sure the stainless steel zipper is facing down slope. Form the flexible base of the flashing to mirror the roof panel and apply sealant under the base. Press the base of the flashing against the roof panel and use #14×11/8-inch T1 self drilling stitch fasteners with a sealing washer every 1-inch to 1 1/2-inch around the perimeter of the flashing to fasten the flashing to the roof panel.
Jerod Webber is sales manager at Dynamic Fastener, Raytown, Mo. To learn more, visit www.dynamicfastener.com or call (800) 821-5448.
