What Types of Pipes Can and Cannot Be Relined?

Est. Reading: 3 minutes

Most residential sewer and stormwater pipes can be relined, including clay, earthenware, cast iron and concrete, and PVC too, where it is damaged or leaking. What usually rules relining out is the pipe's condition, not its material. Crushed or collapsed sections, badly offset joints, sagging pipes and blockages that cannot be cleared are the main deal-breakers.

Key takeaways / Quick Answer

  • Industry guidance from the US-based National Association of Sewer Service Companies (NASSCO) says cured-in-place lining suits "all types of host pipe material and shapes".
  • The existing pipe has to be clear of obstructions and crushed or collapsed sections, and it can't have lost more than 40% of its cross-section.
  • The new liner keeps the existing line and grade, so it cannot fix a sag or a badly offset joint.
  • Cracks, roots, leaky joints and corrosion are the sweet spot. These are the problems trenchless pipe relining is made for.

5 Types Of Pipes That Can Usually Be Relined

NASSCO's pipe rehabilitation matrix lists CIPP as suitable for all host pipe materials and shapes. In everyday Sydney terms, here is how the common materials stack up.

1. Clay and earthenware pipes

If your home was built decades ago, there is a good chance your underground drains are clay or earthenware. They are tough, but they are laid in short lengths with lots of joints, and those joints are where roots love to sneak in. Relining seals the whole run with one continuous liner, so there are no gaps left for roots to find.

2. Cast iron pipes

Cast iron can corrode, scale up and develop rough internal walls that catch waste. Relining restores a smooth inner surface. The pipe is cleaned first, because a liner needs a clean surface to bond to.

3. Concrete pipes

Concrete can crack and corrode over time. A liner seals the cracks and gives the line a new, smooth interior without excavating.

4. PVC and plastic pipes

PVC is newer and generally more durable, so it needs relining less often. When it does need help, such as after damage or leaking joints, it can be relined. Your plumber will assess whether relining or a small spot repair makes more sense.

5. Stormwater pipes and branch lines

Relining is not limited to your main sewer. It can also be used on stormwater drains and shorter branch lines, and after the liner cures the connections are reopened so everything flows again.

7 Pipes That Cannot Be Relined (or need a different fix)

Here is where we have to be straight with you. Relining is not magic, and a good, licensed plumber will tell you when it is not the right answer.

1. Severely collapsed or crushed pipes

If a section has caved in, there is no open pipe for the liner to travel through, and the usual fix is to excavate that section.

2. Badly offset joints

Where two lengths of pipe have shifted so far apart that they no longer line up, a liner cannot correct it. Industry guidance notes that CIPP cannot correct severely offset joints. Slight misalignment is generally fine, but major displacement is not.

3. Sagging or bellied pipes

A relined pipe keeps the same line and grade as the old one. So if your pipe has sunk and holds water in a low spot (a "belly"), the liner will follow the same dip. The sag stays, and so can the problem.

4. Pipes with obstructions that cannot be cleared

The old pipe needs to be clear before lining. Roots, scale and debris can usually be cleared with high-pressure jetting and cutting. A solid blockage from something like a collapsed section or a hard intrusion is a different story.

5. Large missing sections or holes

If big chunks of the pipe are missing, the liner can balloon into the empty space instead of pressing against the wall. A camera will show whether the damage is a crack, which relining handles well, or a hole too large to line.

6. Pressurised water supply pipes

The pipes carrying drinking water to your taps work under pressure and are a different job with a different method. If you think you have a leak in a water supply line, speak to a licensed plumber.

7. Pipes with no workable access

Trenchless pipe relining needs a way to get the liner in, even if it is only a small opening. In rare cases where there is no practical access point, your plumber may need to create one or choose another approach.

Why a CCTV inspection Decides Everything

A reliable relining quote starts with a camera, not a guess. A good CCTV drain camera inspection shows:

  • The pipe material and approximate condition
  • Where the damage is and how bad it is
  • Whether roots, scale or debris are present
  • Whether there are collapses, sags or offset joints
  • Whether your pipe is a good candidate for a sewer reline, a spot repair or excavation

It also gives you evidence. Footage means you can see the problem for yourself rather than taking anyone's word for it.

Blocked sewer repair: is relining the answer?

If your sewer is blocked, the first job is to clear it. The second job, which often gets skipped, is to find out why it blocked. If the cause is build-up, a good clean may be all you need. If the camera shows cracks, roots or leaking joints, a sewer reline can stop the problem coming back. Our blocked sewer team and blocked drains and pipes service can help, 24/7.

Not Sure If Your Pipe Can Be Relined? Let's Find Out.

Sydney Drain Surgeons will inspect your pipe, explain what we see based on real-time footage and tell you honestly whether relining is the right call.

Ready to talk to a local expert about pipe relining in Sydney? Contact our pipe relining specialist today. Or click Enquire Now.

In this blog

Most Frequently Asked Questions

How long does pipe relining last?
Professional pipe relining typically lasts 20-50 years, with many installations exceeding 50 years when properly maintained.
Is pipe relining cheaper than replacement?
Yes, pipe relining is significantly more affordable than traditional excavation and replacement, often costing 30-50% less when you factor in restoration costs.
How long does the pipe relining process take?
Most pipe relining jobs are completed within one day, though complex projects may require additional time.
Will pipe relining work for my property?
Pipe relining is suitable for most residential and commercial properties. Our CCTV inspection will determine if your pipes are good candidates for relining.
Do you offer warranties on pipe relining Sydney services?
Yes, we provide a lifetime guarantee on all our pipe relining work, plus free drain camera inspections for 2 years.

What types of pipes can be relined ?
Pipes made of any material can be relined including PVC, Copper, Cast Iron, Clay and concrete.

What are the signs of a blocked drain?
The signs of a blocked drain are as follows :
-Foul Smell
-Water overflow
-Gurgling noise
-Slow draining of water
What are the causes of blocked drain?
The most common causes of blocked drains are :
-Tree roots
-Sanitary products
-Oil & Grease
-Mineral, soap or dirt build-up

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