How to Repair a Liner That Didn’t Fully Cure

After pinpointing the cause, it’s vital that a CIPP contractor knows how to effectively deal with a partially cured pipe.
How to Repair a Liner That Didn’t Fully Cure
When a liner cures incorrectly, there’s no going back and starting over; however, it’s also not as bad as you might think at first.

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While trenchless pipe lining is a very effective way to repair compromised pipes beneath roadways, structures or other surface-level objects, it’s not perfect. Nothing is ever 100 percent perfect, both in life and in plumbing. Every type of property renovation project is vulnerable to error; it doesn’t matter if it’s roofing, electrical work or pipe lining, nor what caused the error.

Sooner or later, a liner in a given job will not cure to the desired extent or be washed away during the application process; it’s a risk in any project. When this happens, what’s important is not scrapping the project altogether, and instead identifying the best next steps for solving the problem.

When a liner cures incorrectly, there’s no going back and starting over; however, it’s also not as bad as you might think at first. It’s still possible to reline the pipe without invasive — and expensive — digging. Before this can be done, however, the first step in repairing a faulty or partially cured liner is pinpointing the cause.

Why pipe liners do not fully cure
Generally speaking, there are two main reasons a pipe liner would not fully cure. Either:

  • Water flow within the pipe disrupted the curing process and washed away lining material mid-application; or
  • The compounds in the liner resin were incorrectly mixed, resulting in an incomplete final product

Video inspection should always come first in diagnosing the cause of the liner problem. The same processes and technology that identify initial damage to a pipe can be used to pinpoint why a liner incorrectly cured. Video inspection is the most reliable method of identifying a pipe problem, whether it’s partially cured pipe or a full-blown pipe collapse.

With video inspection tools, we can diagnose the problem by checking the state of the resin (or the complete lack of resin, for that matter). If there’s little or no resin remaining, it’s likely that some source of water flow washed away the resin before curing.

On the other hand, if the resin looks overly saturated and will not cure with conventional methods, the liner compounds are probably mixed incorrectly. Either way, the next steps you should take depend on how much of the liner unsuccessfully cured.

Dealing with a partial curing error
If the lining material did not successfully cure in only a specific segment of pipe (often when lining fails due to water interference), there’s no need to reline the entire length of the pipe in question. Instead, trenchless repair specialists can use sectional point repair to reline the affected segment of pipe, in an overall much more affordable project than relining the entire pipe length.

In sectional point repair for unsuccessfully cured sections of pipe, the affected segment specifically will be relined using an inflatable bladder. As the repair is confined to a specific affected area, the overall process can be completed in a few hours. Sectional point repair is also ideal for dealing with root intrusions and other pipe damage limited to a specific segment of pipe.

What to do when entire pipes do not cure
If entire pipes do not cure correctly (as is often the case when resin compounds are incorrectly mixed), the first step in resolving the problem is attempting to remove the faulty liner via cable inside the pipeline. If the faulty liner can be removed this way, then relining is as simple as starting the process from scratch. However, if the bad liner can’t be removed, the best option is to simply line over the existing liner; this can take longer, but will ultimately solve the problem.

In the worst case scenario, the pipe may have to be excavated using traditional dig-and-replace labor. This is unfortunate, but also 100 percent reliable. Due to the costs of each of these methods, trenchless point repair or re-lining should always be tried first, with excavation saved as a last-resort option.

About the Author
William Heinselman is the owner of Express Sewer & Drain ( based in Rancho Cordova, California, which specializes in plumbing, pipe cleaning, bursting and relining. Heinselman worked 14 years as a supervisor for a sewer district in northern California before opening Express Sewer & Drain with his wife, Sang, a civil engineer.


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