Before a sewer line can be relined it must be cleaned & inspected with a video camera to perform a sewer inspection and  determine that it is in fact a viable candidate for relining. The line must have proper pitch maintained without any bellies, or misaligned joints. The liner follows the contour & path of the original line and will not correct these defects.  The line may have small breaks where pieces of the pipe have broken or fallen out exposing soil but the pipe must maintain it’s original shape and not be collapsing yet. Very short and shallow belly, or, small misalignment may be of no consequence but that is best determined by the experience of the relining contractor as this is a judgment call.

The lining may be shot through any opening in the pipe that that allows good access for the liner to reach the problem area. The liner may even be shot into the line via a cleanout. Cutting into the pipe may also be done. Best access will be determined again by the relining contractor.

The relining material is essentially a woven fiberglass hose with a thin plastic

film on the outside. A calculated amount of fiberglass resin and hardener is mixed then poured inside the liner. the contractor then makes sure that the entire length of the woven fiberglass is fully “wet” with the mixed resin.  The liner is then shot into the the sewer line using a gun that inverts the liner so the resin coated weave ends up on the outside where it bonds to the old pipe and the thin plastic film becomes the slick inside surface of the new pipe. The gun uses compressed air to propel the liner into the pipe and the whole process is very similar to turning a sock inside out.

A calibration tube similar to a balloon is also shot inside the liner which is then pressurized with either compressed air or water heated by a portable boiler. The pressurized calibration tube holds the fiberglass liner out against the existing sewer line until the fiberglass liner cures into a hard new fiberglass one piece pipe within the old pipe. Using the hot water method speeds the curing process. Once the line has cured the calibration tube is removed.

If there are any tie-ins that need to be reestablished a small device with a

cutting burr is inserted into the pipe to cut out openings allowing flows from the other line to flow into the newly relined pipe. At this point the work on the line is done, a quick video inspection to check the line,  and the relined sewer is ready for use.

While the relining process sounds very easy in this description I assure you that what I have written is an oversimplification. The sewer line must be cleaned very well prior to relining, and the process requires a careful choreography that even highly experienced crews stop to talk about just before the resin is mixed. The job has a very high pucker factor that comes in as soon as the hardener is added to the resin. At that point the clock is ticking with a count down to the time at which the resin used to impregnate the liner hardens. If the liner hardens before you have completed pressurizing the balloon line you are in trouble.

There are a few different relining processes from different manufacturers used. This article is intended as an overview of the process and is not a full description of every different manufacturers process.

I hope this article gives you a good understanding of the sewer line relining process, the steps involved in the relining process, and the limitations of the relining process.  The net result is a new one piece pipe within the old pipe that does not leak and is impervious to root intrusion.

If you are having problems with your sewer line or your septic tank you may have to call a plumber to figure out what could be wrong with your drain lines. There are many tools that the plumber can use to find out what is wrong with the sewer line including drain cleaning machines, sewer inspection camera’s and something called a pipe bursting machine.

The pipe bursting machine is one of the best options for the replacement of an existing  sewer line and this process that plumbers using this machine is called pipe bursting. A  licensed plumbing contractor can use this method to excavate and expose the old pipe which is connected to the septic tank or the city sewer system.

The starting  point would typically be in the street where the plumber would locate the sewer lateral (the sewer line from the house to the city sewer line in the street) that connects to the city sewer or your septic tank like we mentioned above.

The other hole  would be either just outside the foundation where the line exits the house, or, in the basement just before the line exits the house. A strong steel wire rope cable is pulled through the sewer lateral between those two points. A cone shaped bursting head is attached to the cable along with the new polyethylene pipe which is attached behind the cone shaped bursting head.  At the other end a hydraulic puller is placed which takes hold of the cable and pulls it with great force in a series of short strokes. Typically speeds are in the area of 10 – 15′ per hour. The cone shaped bursting head goes through the old sewer line expanding it over the cone until the old pipe bursts creating room for the new High Density Polyethylene Pipe (HDPE) to be pulled through the ground where the old pipe was. Lengths of the HDPE pipe are joined together using a plastic welding process that creates a new seamless one piece sewer line with no joints that can leak or, be penetrated by roots. Once the line is pulled through between the two holes the connection to the house and the city sewer is reestablished and the line has been replaced.

There are some limitations to using the pipe bursting process:

The first is the line has to be in good enough condition for the cable to be pulled through the line.

Pipe Bursting will not fix a sag, or, belly. The bursting head and new pipe follows the path of the old pipe.

Rocks, ledge and some other conditions may jam the bursting head preventing it from passing and still require excavation to complete the job.

Some bend configurations may not allow pipe bursting as the bursting head may exit the pipe and get stuck requiring excavation.