Commercial Roofing Construction Detail: Flashing A Pipe With Liquid Applied Flashing (CTL-SF-06)


Hello Commercial Roofing Warriors,

Joe here, and I’m back to share my knowledge about low-slope roofing! My goal is to help you and your team learn the best application methods for a successful and leak free Commercial Roofing system install.

Let’s Get Started! 

For this session, I’ll be walking you through the steps used to flash a pipe with SmartFlash® ONE, our liquid-applied flashing (Construction Detail CTL-SF-06). As you know, penetrations can be very challenging, and are typically the culprit when it comes to leaks. This is why I often tell contractors in my training sessions that “the devil is in the details.”

So, in order to protect a building and its contents from water damage, you must make sure all penetrations have been flashed with high-quality products using the appropriate application method. Your reputation may depend on it! 

Our SmartFlash ONE is a one-part liquid-applied flashing that provides a watertight seal over the detail, locking out moisture. Liquid-applied flashing is a great product that allows for broad coverage, limiting the stress of precision application around penetrations, and is required for a CertainTeed warranty on any penetration with a height below 8″ from the roof system.

1. First, prepare your field membrane using the Flintlastic® SA Cap. Make sure it is in place, then cut a hole to accommodate the pipe’s width.

You’re Now Ready To Flash In 

2. Start by roughing up the pipe.

3. Then, prepare the polyester fabric reinforcement by wrapping the fabric around the pipe, measuring a 2” overlap.

4. Now, cut fingers into the bottom half, allowing the fabric to radiate around the pipe.

5. Next, we need our target patch; this will sit on top of the fingers. You’ll take 6″ on each side, overlapped by 2″ in the middle. Finally, cut out the fabric to accommodate the width of the pipe.

6. For a clean finish, tape off both the edges and pipe 1” beyond the reinforcement.

You’re Now Ready for Resin

7. SmartFlash ONE is thick and can be applied easily with a brush or roller without dripping. First, apply the resin around the pipe and onto the base at approximately 30 wet mils thick. 

8. Then lightly press in your finger flashings. 

9. Now fully cover the fabric with resin, making sure to put resin in the 2” overlap. You should not see any fabric. 

10. Next, press in your target patch. Again, be sure to fully coat the surface and overlapping area with resin.

2-4 Hours Later… 

11. For full 20-year warranty coverage, allow two to four hours to dry, and then apply a final coat, approximately 30 wet mils thick.

12. For aesthetic purposes (not required for warranty) add CertainTeed color-matched granules into the wet resin.

Congratulations! You’ve just added a very important roofing installation technique to your skillset! If you have any questions, you can submit via this form or leave a comment below. 

For additional information on CertainTeed products and installation, please visit, or go directly to our Flintlastic SA Installation Manual

In the meantime, keep an eye out for my next blog and video post detailing the installation method for flashing a drain!

Happy Building, 


Find all our Construction Details here:—roof-systems-specifications/

Learn more about How to Flash a Pipe (CT-13)


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