Branch Line Tie-Ins Cause Problems

“I just got a call back from a lining job I completed using a pull in place method. I followed the gapping method of cutting out an oversized section of the liner to avoid cutting out the branch lines. Everything went in as planned and I was proud of providing a permanent solution only to have the wheels come off the job and now am facing a lawsuit unless I fix the problem. The problem is this, each branch line comes from an individual apartment on the horizontal plane. When it gets to the stack, the wastewater spills down the newly lined pipe but some of the wastewater is getting between the liner and the original pipe and staining the vertical walls on several floors of the building. A video inspection shows everything is in place, just as I left it. My question is this: shouldn’t the liner prevent the wastewater from seeping between the liner and the original pipe?”

CIPP liner is classified as a “close fit” process and while it can be designed to be a stand-alone pipe replacement it does not seal or bond with the host pipe and will allow wastewater to flow between the two. This is the reason that the UPC banned the application of CIPP liner to cast iron pipe inside a building. But there are a couple of options that may solve the problem and save a future lawsuit. Before we get to the solution for this particular problem, let’s look at other methods that could have helped from the get-go.

There are a number of ways to rehabilitate a plumbing stack. Obviously, you could open the walls, replace the cast iron pipe with new cast iron, PVC or ABS pipe and no hub it back in place. This solution is the reason you and your customer choose another option.

Moving from this solution we offer a CIPP solution that uses liners and branch line connections to build a new stack in steps starting at the lowest level and building a watertight new pipe inside the old pipe. At each tie-in, we have a CIPP wye or tee that is placed and cured up the branch line. It works like this.

  • The first segment of the stack is lined to within a foot of the first tie in.
  • After that is cured, a wye or tee, depending on the pipe tie-in is prepared and put in place covering the first segment of the vertical stack. This ensures sewage will not penetrate the joint as it is overlapped similar to overlapping shingles on a roof. The branch line is lined up the branch and the top is located in the stack. This section is cured.
  • Moving upstream of the branch, subsequent CIPP sections are installed building a new pipe that is leak proof as the material is cured and sewage flows through the sealed system.
  • The next section of the stack is prepared and installed covering the wye or tee and traveling up to the next tie in. This process is continued which provides a fully sealed plumbing system built entirely inside the host pipe.

For those looking for other solutions, UPC & IPC codes allow for the application of polyurea resin to coat and seal the pipe. Unlike CIPP resins that tend to shrink slightly on curing, polyurea expands slightly on curing and seals tightly to the host pipe preventing the tracking found in the regular CIPP process. This process is employed delivering a fast set resin to a set of brushes to mix and apply the materials to the cleaned host pipe. As you have the ability to brush coat all of the tie ins you prevent water from traveling between the host pipe and the coating, eliminating the water leaching out into the spaces where there were leaks in the original pipe that you were hired to fix. The coating process cures fully after 5 minutes allowing the single installer to build thickness to meet the need of the client.

Now to address your particular problem without having to tear out all of the lined pipe with the process you used originally. You could clean the lines around the original gaps in the method you used. You can brush coat the liner to seal it from water migration and continue to those areas where any liners end and original pipe begins. You can apply this fix in place.

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

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