What Is Trenchless Sewer Repair (Types, Cost, Pros & Cons)

  • Post author:
  • Post last modified:October 17, 2021
You are currently viewing What Is Trenchless Sewer Repair (Types, Cost, Pros & Cons)

Let’s say you need to fix or replace a pipe in the yard, under the patio, or under a concrete floor. What do you do? Do you make a huge mess while digging a trench to get to it? There are technologies that fall under ‘trenchless sewer repair’ that could help you immensely.

What Is Trenchless Sewer Repair? Trenchless sewer repair is a way of fixing the corroded or backed-up pipes under your homes or buildings, so you don’t have to dig them up to replace them. There are two main types of doing this: pipe bursting and pipe lining.

What’s great about this approach is that it’s a much faster and cleaner way to fix your pipes, and it can often be done in just one day. Most of the time, you can keep using your plumbing while the work is in progress, except for a few hours a day.

US Environmental Protection Agency website suggested nicely that trenchless sewer repair methods are particularly valuable in urban environments because it causes fewer construction impacts that are disruptive to businesses, homeowners, and automotive and pedestrian traffic.

Check out some of my other articles for the Homeowner: Can You Mow After It Rains?, How Long for Asphalt to Dry? and Car Window Replacement Cost – When to Involve Insurance?)

What Is Trenchless Sewer Repair?

Putting it simply, trenchless sewer repair is sewer pipe repair without digging a trench.

Trenchless pipe repair (trenchless plumbing) is a way of fixing your drainpipes by using modern technologies of pipelining, and pipe bursting.

Cast iron pipes break all the time and they mostly break on the bottom. This is because of the water flow on the bottom, which is where most of the corrosion happens. Over time, the pipe gets thinner and eventually cracks. This crack widens, and now your pipe gets filled with dirt, which creates a blockage as well.

This happens all the time, and to fix this in the past they needed to dig a trench in your yard, or next to your building, making a huge mess.

Trenchless drain pipe repair is the solution to this. The contractor will dig one or two access points (the 2nd one usually being outside of your property). Sometimes a manhole is used as an access point without digging. This makes it a much cleaner and efficient way of fixing sewer lines, which is why trenchless sewer line replacement is the future of sewer line repair.

Benefits of Trenchless Sewer Repair

  • No excavation required
  • Fixed price compared to traditional excavation method
  • No permitting and no inspections are required
  • Cleaner and faster way to fix your sewer pipes
  • More environmentally friendly than excavation
  • Fixed pipes will last for 50 to 100 years

Types of Trenchless Sewer Repair

The main types of trenchless sewer repair are:

  • pipe bursting,
  • pipe lining, and
  • sliplining.

Some of them appeared just a few years ago, while others have existed since the late 1990s.

All of these technologies are used to fix your sewer line without destroying the yard or digging a trench.

Pipe Bursting

Pipe bursting is a form of trenchless sewer line replacement where a new pipe is pulled through the existing one, which breaks the old one and you get a completely new pipe. The old pipe is broken in place (burst) with a bursting cone, which pushes the surrounding soil so that the new pipe can fit in.

The United States Environmental Protection Agency website explains pipe bursting in finer detail.

trenchless sewer repair pipe bursting method

The old pipe is broken by fracturing or splitting. This will depend on the material of the old pipe.

For example, if the old pipe is made from:

  • Clay,
  • Concrete,
  • Cast iron, or
  • PVC,

the old pipe will be broken (fractured).

If, however, the old pipe is made from:

  • Ductile iron,
  • Steel, or
  • HDPE,

the old pipe will be split.

Regardless of how the old pipe is broken, in the end it will be replaced with a completely new pipe, which lasts for 50 years at least. Pipe bursting has been proven for decades around the world as a viable option to replace failed underground pipes.

The process of pipe bursting goes like this:

  • Digging two access points to access the pipe on two sides
  • Running a cable line from one side of the pipe to the other, where the pulling machine is positioned
  • Attaching a bursting cone to the new pipe, and pulling it with cable from one point of the ‘old’ pipe to the other
  • The new pipe breaks (bursts) the old one, and now you have a completely new pipe in place.

Here’s a short video explaining pipe bursting:

Pipe Lining

Pipe lining is a form of trenchless plumbing where the cracks in the pipe are fixed by epoxy-resin mixture. This mixture is cast on the walls to fix the breaks, or it gets hardened on the inside to form a stronger pipe within the old one.

There are two types of technologies for trenchless pipe lining:

  1. Spin cast pipe lining
  2. Cured-in-place pipe lining

Spin cast pipe lining

Spin cast pipe lining technology exists since 1998, and it’s also called pipe coating. It is widely used as a way of trenchless sewer repair for pipes with a lot of twists and turns. For spin casting, the repair crew generally only needs one access point, usually outside of your property, to access the main pipe.

It’s highly cost-effective and frequently used, with a design life of 75 years.

The process of spin-cast pipe lining is simple:

  • first, the pipe is cleaned of all dirt and residue
  • next, an epoxy-resin mixture is pumped out of a tube into the pipe
  • inside the pipe, a machine spins and casts the mixture onto the walls of the pipe
  • it is then left to cure for several hours, after which the process is repeated

This mixture becomes very strong, stops all corrosion and it can protect your pipe for 50 years at least.

Cured-in-place pipe lining (CIPP)

Cured-in-place pipe lining (CIPP) is a very popular trenchless method of sewer construction that ultimately creates a completely new pipe inside the old one, and it takes a relatively short time to complete.

trenchless sewer repair pipe lining lateral view

CIPP method creates a very strong pipe, which is resistant to almost anything, even tree roots. The process uses several layers of materials that go into the pipe.

First, we have an outside fabric that is coated with a termosetting resin. When they are mixed, it causes the material to react and heat up to about 180 degrees, after which it turns into a rock.

This fabric is separated with another layer from the balloons that act as the middle and from the bottom layers. These balloons are pumped with air to get the outside fabric to stick to the pipe.

After about 4 hours, the balloons are removed and leave behind your relined pipe. After this, the pipe is inspected with a camera for any potentially missed spots, cracks, and dimples. The pipe is now completely covered from the inside with this white rock-like material that fixed all the cracks and protects it from the inside for at least 50 years.

So even if your pipe cracks again, it has this artificial pipe inside it, that is way stronger and can even stop tree roots from damaging it.

The city of Portland website goes into more detail about the benefit of the CIPP method of trenchless sewer repair.

Here’s an excellent video on pipe lining by Hugo Forster:

Check out my articles for the Homeowner: Can You Mow After It Rains?, How Long for Asphalt to Dry? and Car Window Replacement Cost – When to Involve Insurance?)

Sliplining

Sliplining is a well-established trenchless method of putting another pipe if a smaller diameter inside your existing pipe.

The space between the existing pipe and the new pipe is typically grouted to prevent leaks and to provide structural integrity.

For sliplining, an insertion pit must be dug for each pipeline segment, and because of this, in most applications, sliplining is not a completely trenchless technique. However, even this amount of excavation is far less than what is needed for a traditional excavation method of sewer line repair.

Trenchless Sewer Repair Cost

On average, trenchless sewer repair cost from $80 to $200 per linear foot of lining, for residential purposes, and from $130 to $260 per linear foot for commercial purposes.

The cost of trenchless sewer repair varies by pipe diameter, installation complexity, and length. Also, it’s generally less expensive to install outside of a building than under it because of the installation method involved.

Note that every trenchless pipe lining company will have a minimum charge in order to mobilize their expensive equipment and trained crew.

Trenchless Pipe Bursting Cost

Replacement of pipes by trenchless pipe bursting costs around $80 to 200 per linear foot.

For example, the entire job could cost you anywhere from $4000 to $6000 for a smaller job, and up to $12000+ for bigger repairs. The price will vary depending on pipe diameter, installation complexity, and length.

Trenchless Pipe Lining Cost

Trenchless pipe lining costs around $80 to $200 per linear foot. The entire job could cost you anywhere from $4000 to $12000 on average. Like pipe bursting, the price will vary depending on pipe diameter, installation complexity, and length.

The best way to reduce your costs for trenchless sewer repair jobs is to call several companies, get quotes, and then pick the one that best suits your need.

Traditional vs Trenchless Sewer Repair Cost

Traditional excavations can often be cheaper than trenchless sewer repair, but the costs can easily jump if you have any kind of utilities or obstacles above the pipe.

The cost for a traditional dig pipe repair is around $50 to $250 per foot, and the entire job will cost $3000 to $6000 on average on a small scale. However, traditional excavation costs can raise easily beyond 12k, up to 20k for any additional obstacle and difficulty the team encounters.

In comparison, there usually aren’t any obstacles for trenchless sewer repair, and the price generally stays at a fixed rate per linear foot because the job is done through the old pipe. There is no excavation, no digging next to tree roots, no additional damage other than the one or two access points of several feet wide that the crew needs to make. Sometimes even manhole access is enough.

Trenchless Sewer Repair Pros and Cons

Spin cast pipe lining pros

  • cost-effective
  • the design life of 75 years
  • intersections and branches get lined completely
  • can go through multiple bends without a problem

Spin cast pipe lining cons

  • slightly thinner than cured-in-place pipe lining (usually not a problem)

Cured-in-place pipe lining pros

  • significantly less time to complete than other sewer repair methods
  • better protection than spin cast pipe lining
  • can protect against tree roots and pipes on the outside of the house

Cured-in-place pipe lining cons

  • doesn’t cover an intersection of pipes
  • can’t cover too many twists and turns. If it gets stuck you’ll need to excavate through the floor or under the house to get it out
  • if not positioned properly in the intersection of the pipes, the connection can be covered up and it can cause backups (must be fixed and polished up later on)
  • requires two access points, sometimes through the house, and sometimes through the outside walls of your house

Here’s a cool video on Cured-in-Place-Pipe Lining (CIPP):

Trenchless Sewer Repair Equipment

For those getting into the business of trenchless sewer repair, there’s a range of equipment items necessary for most trenchless sewer repair jobs.

Here is the most common trenchless sewer repair equipment:

  • Pulling unit
  • Power supply unit
  • Hydraulic pumps for bursting
  • bursting heads of several sizes
  • Fusion units for pipe fusion
  • cylinder head
  • cylinder clamp
  • assembly sheave
  • burst heads of several sizes
  • More accessories and parts:
    • sheave assembly
    • tapered jaw
    • clamps
    • blade sets
    • cable grip tool
    • lever bracket
    • cylinder clamp seals
    • and a few more.

The first few items of sewer repair equipment cost several thousand dollars, and the rest are much cheaper. As you can see, it’s a big investment to get everything set up, but it’s definitely worth it, and the business has great potential in the future.


The trenchless sewer repair business is growing, and it’s the future of sewer pipe repairs.