Confused Between Lining & Coating?

“We lined several vent stacks and have had a few of them leak. We used the CIPP method sold to us using a “gapping method” that they told me would work well for fixing in plumbing stacks. We thought that the lining process would seal the old pipe and prevent leaking. Now I read that you have a process to seal up those pipes that are leaking. What’s the deal? Why didn’t the original CIPP process seal all the leaks and only a few of them were sealed? Is this a better CIPP process than what we were using?

Let’s start with the last question first. The coating process by Pipe Lining Supply’s Quik-Coating system is not CIPP. The CIPP process involves saturating a fabric tube with either epoxy, polyester or vinyl ester resins, inserting it in the old pipe and expanding it until it is cured.

Coating Example

The Quik-Coating system process uses a different resin system that complies with the Uniform Plumbing Code and the International Plumbing Code standards. These standards outline a method of applying the resin system over the surface of the host pipe without any fabric. This system is referred to as the Applied In Place Pipe Rehabilitation (AIPPR) process.  It works in conjunction with the host pipe but doesn’t act as a replacement for the host pipe by rebuilding the pipe creating a hybrid pipe that relies on filling in cracks and voids with a resin material that hardens very quickly. When completed the hybrid pipe has been reconstructed to operate under gravity sewer conditions and pass a gravity sewer pressure test.

In answer to why some of your lined pipes failed the CIPP process is that a virtual pipe-replacement pipe-rehabilitation process is where the old pipe is used as a form to house the tube and resin combination that’s considered a stand-alone pipe when cured. The new pipe formed is considered a “close fit” pipe built inside the old pipe but may not fit close enough to “seal” the walls between the old pipe and the new one. Because of this water can and will track between the old pipe and the new. When you cut the openings for each of the branch lines feeding into the stack, water may work its way between the old and new pipe in the gap and gravity takes it down the wall. Depending on the volume and the building wall material you may see evidence of this tracking stain on a wall or ceiling. That’s where the leaks appear.

CIPP Lining

The resins used in the CIPP process all shrink to a degree. Some shrink more than others and over the years many products were offered to seal the gap between the host pipe and the liners. The resin formulation we use in the Quik-Coating AIPPR process expands slightly during the curing process. Because of this expansion, and the configuration of the round pipe containing the resin expansion, the resin expands enough to seal the water from tracking found in the CIPP process.

Here’s where AIPPR excels in rehabilitating DWV pipe with branch lines. The coating uses the remaining value in the old pipe to form a water-tight hybrid pipe. If the host pipe is found to be fully deteriorated and not capable of being rebuilt to a viable hybrid pipe, you can insert your CIPP liner to provide a stand-alone replacement pipe using your gap method or another method in which you reinstate the branch lines with a cutting device to open the branch where the liner covered it. The Quik-Coating process can then be employed to seal the liner to the host pipe at each branch line tie-in by applying the coating material to the pipe covering both the exposed host pipe and the new liner. In the event the pipe is determined to be rebuildable you could use the coating process as a fix by itself.

In summary, these are two completely different processes and should not be confused with each other. They conform to different standards and meet different testing processes.

For more information contact Pipe Lining Supply at +1-888-354-6464 or email us at

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