The average person rarely thinks about their sewer pipes.  That is, until the sewer pipes are no longer functioning properly.  Once the pipes become a problem, they’re often the only part of the property a person can think about.  At this point, all parties involved want to find the quickest solution to a nasty issue.  Trenchless sewer repair can often be the solution.

So how does trenchless sewer repair work?  Trenchless sewer repair works by adding a pipe liner to the inside of the existing pipe structure.  Once installed, this liner is expanded and then hardened.  The hardened pipe liner then becomes a part of the pipeline itself, thus eliminating the need to remove the damaged section of piping to install a new pipeline.

Trenchless Sewer Repair From Start to Finish

Trenchless Sewer Repair

Trenchless Sewer Repair, courtesy of US Department of Agriculture

Step 1 – Identify the cause of the problem

Before doing any repairs, a technician will be brought in to send a camera down the sewer line.  The camera will show the technician the source of the problem so that it can be appropriately dealt with.

There can be many causes for broken sewer lines, but some of the more common ones are root infiltration and rusting.  Older cast iron pipes are known to rust-out over time.  Clay pipe deteriorates within fifty to sixty years.  Even newer pipelines can be susceptible to invasive tree roots.  For example, a willow tree’s root system can easily extend up to 35 feet.  These roots will seek out moisture wherever they can find it, and a sewer line will not be strong enough to defend against these roots.

Step 2 – Eliminate the Source of the Problem

Once the technician has identified the cause of the problem, he or she can work to eliminate it before applying any repairs.  For example, the homeowner or business may want to take steps to remove the offending tree so that it cannot attack the pipes again after they’ve been repaired.

Step 3 – Remove Obstructions Within the Sewer Line

The next step in any trenchless sewer repair project is to remove any obstructions within the pipe.  This is usually done by hydro jetting the line.  Hydro jetting is simply the act of using water under high pressure to clean the inside of the pipes.  This is done through the use of a long hose which is inserted into the downstream pipe and then snaked through to the obstruction.

Hydro jetting can easily remove any roots, scale, or soil that has built up within the pipe.  This process can also be used to remove obstructions in pipes that are clogged but not yet damaged.  For instance, a homeowner may have to hire a plumber to hydro jet their pipes after a significant accumulation of grease has built up in them.

After hydro jetting is complete, a technician will once again send a camera down the pipe to complete a video inspection.  The video inspection will then be used to create a pipe liner that will run the entire length of the damaged area.  This video inspection will let the installers know how long the liner will need to be as well as the locations of the incoming pipes.  The locations of the incoming pipes are important as the liner may need to be cut into each connection.  The reason for this is that the connections can be up to twice as thick as the original piping.

Step 4 – Building the Sewer Pipe Liner

A trenchless sewer repair pipe liner will initially consist of four different layers.  Each of these layers will fit into each other, and they all satisfy different yet critical roles. A fifth layer is also used in most cases and included in the list below:

  • The innermost layer is an inner tape that prevents the other layers from stretching during installation.  This tape is usually blue and looks similar to what you’d expect painter’s trim tape to look like.
  • A black rubber bladder makes up the second innermost layer.  This layer will eventually be inflated to push the outermost lining against the wall of the pipe.  It will expand with enough force to break through the tape.
  • The next layer is a plastic liner that prevents the rubber bladder from sticking to the lining.  This will allow the bladder to be used to shape the final layer while inflated without pulling it back in when it is deflated.
  • The outermost layer is the layer that will ultimately stay inside the pipe.  It is typically made from fiberglass cloth, but can consist of other materials as well.  This layer is usually treated with a self-heating epoxy resin that is impregnated into the material.  A technician applies the epoxy while the material is still flat.  They do this through the use of a heavy roller that physically pushes the epoxy into the material.  It’s essential that the resin fully saturates through the material or it will not cure correctly.
  • In most cases, a fifth layer is added to the outside of the fiberglass layer.  This is another plastic layer, and it keeps the epoxy locked into place.  Because epoxy will not stick to plastic, it creates a perfect barrier.  Tape can be used again on this layer as the inflated tubing will easily break through it.

Step 5 – Trenchless Sewer Repair Installation

Before the pipe liner hardens, it must be put into place.  Once the pipe liner is prepared, it is put onto a reel.  This reel is brought to the job site, and a line is strung from the upstream access point to a downstream access point.  The upstream access point could be a clean-out, and the downstream access point could be a manhole.  After the line has been pulled through, the pipe liner is attached, and the line is used to pull the pipe liner into place.

In some instances, once the epoxy is applied, the process begins to become time-sensitive as the epoxy is already working to harden the material.  Other methods for hardening the epoxy include steam curing, using ultraviolet lights or other heating devices to help activate the chemical properties of the epoxy and to speed up the curing time.  Once the epoxy has fully cured, the fabric will become the new pipe.  This is often referred to as a cured-in-place pipe.

Advantages of Trenchless Sewer Repair

Imagine having to use a portable toilet in your backyard for a week this winter because your sewer pipes are undergoing extensive repair! This illustrates how advantageous trenchless sewer repair can be.  Here are some of the benefits:

  • The site will not need to be excavated.
  • Repairs are completed quickly.
  • The process costs less money than traditional pipe repair.

The primary advantage of trenchless sewer repair is that it can be completed without excavating the site.  In the past, the process of repairing a broken pipe would start with a construction crew excavating the site.  If this were under a person’s house, they’d have to tear up the home owner’s floor.

Next, the repair crew would have to cut out the pipe and replace it using new piping and new pipe fittings.  Once this was completed, they would test the pipe and then begin the lengthy process of putting the home owner’s house back together.  All the while, the home would be exposed to dangerous sewer bacteria, and the homeowner would not be able to use their plumbing.

For businesses, the situation could be even worse.  Imagine the problems a broken sewer pipe might cause for a large rental community.  The management company might have to pay for all of the residents to stay at a hotel while the repairs were being completed.  A repair of this magnitude might take weeks to complete.

Not only is there the expense and timeline issues, but sometimes excavating a home can be dangerous.  Older homes may have asbestos insulation or encapsulated lead paint between the walls and the broken pipe.  To legally remove asbestos from a commercial building requires the use of a certified abatement professional.  These professionals can be expensive, and they can sometimes be hard to find.  If you have to wait on a plumber, a construction crew, and an abatement specialist to fix your pipe, you may be waiting a long time.

With trenchless sewer repair, this is all avoided as excavation is not needed.  This dramatically reduces the time and money involved in repairing the home owner’s pipe.  In fact, most repairs can be completed in less than four hours.

Related Questions

Does Trenchless Sewer Repair Decrease the Width of the Pipe?

This is the most commonly asked question about trenchless sewer repair.  Since the pipe liner will fit inside of the existing pipe, it stands to reason that it will need to be smaller.  However, the difference is negligible, and in most applications, the new pipe’s diameter will only be about 5% smaller.  This slight reduction in size will not cause any noticeable difference in the flow of water inside a person’s home or business.

Can I Snake the Drain Instead of Hydro Jetting It?

This will depend on the severity of the obstruction.  In most cases, however, snaking the drain will not be sufficient enough to clear the drain out completely.  If the drain is not entirely cleared, the pipe liner will not be able to be inserted, and the repair will not be able to take place.

Milestone Companies Sewer Repair Services

The state of many municipalities’ sewer lines is frequently aged and in need of repair or replacement.  Milestone has many years of experience in sewer line repairs.  We focus on sewer infrastructure rehabilitation, civil sewer repair services, as well as new sewer infrastructure construction.  We can provide the most economical solution to meet the needs of any municipality to keep this extremely important part of our infrastructure flowing smooth! To see more, check out our civil and infrastructure services page.