Pipe relining has earned its reputation as one of the most effective ways to repair a damaged drain without digging, but it is not foolproof. When homeowners start comparing Pipe Relining Melbourne providers, few realise that the difference between a liner that lasts for decades and one that fails within a few years usually comes down to preparation, materials and installation technique. The good news is that most relining failures are preventable, and knowing what causes them is the best protection you have before signing a quote.
Can Pipe Relining Fail?
Yes. A properly prepared and installed liner has a strong long-term track record, but a poorly executed one can fail early. Industry reporting on cured-in-place pipe (CIPP) consistently points in the same direction: most problems are caused by shortcuts in cleaning, resin handling, curing or junction work, not by a flaw in the technology itself. In other words, when relining fails, it is usually the job that failed, not the method.
The 7 Most Common Reasons a Pipe Liner Fails
1. The Old Pipe Wasn’t Cleaned Properly
This is the most common cause of relining failure. Before a liner goes in, the host pipe needs to be thoroughly cleaned with high-pressure jetting and, where needed, root cutting or descaling. If grease, scale, sediment or root fragments are left behind, the resin cannot bond to the pipe wall in those areas. Water can then track behind the liner, and the repair starts failing long before it should. Preparation is not an optional extra on a relining quote, it is the foundation the whole job sits on.
2. The Resin Wasn’t Correctly Mixed or Saturated
Relining resin is mixed with a hardener at a precise ratio, then impregnated into the liner so the material is evenly saturated from end to end. Get the ratio wrong, or leave air pockets during saturation, and the cured liner can end up with dry spots, soft sections or weak areas that never reach their intended strength. Experienced installers measure the amount of resin needed for the pipe’s diameter and length, and saturate the liner under controlled conditions to avoid exactly this problem.
3. Moisture Interfered With Curing
Resin needs the right conditions to cure fully. Water flowing through the pipe, groundwater seeping in through cracks, or moisture sitting in the line during installation can interfere with curing and leave sections under-cured. An under-cured liner may look acceptable at first but lack the structural strength and chemical resistance it is supposed to have. Managing water flow and controlling curing time and temperature are part of doing the job properly, not something to leave to chance.
4. The Wrong Liner or Resin Was Used
Not every liner and resin system suits every pipe. The materials need to be compatible with the host pipe, whether that is clay, cast iron or PVC, and with the conditions the pipe operates in. A system that is poorly matched to the pipe’s diameter, bends or environment is more likely to fail even if the installation itself was otherwise sound. In Australia, relining products must also hold WaterMark certification, so it is reasonable to ask exactly which system will be used in your pipe and confirm it is certified.
5. The Liner Wrinkled During Installation
Wrinkles and folds are among the most commonly documented relining defects. They tend to form at bends, changes in pipe diameter, or where the liner bunches during inversion or pull-in. Minor wrinkles running along the pipe may fall within acceptable tolerance, but larger folds running around the pipe can reduce flow capacity and create a ledge where debris and grease collect. That can recreate the same blockage problems the relining was meant to solve in the first place.
6. The Liner Separated From the Host Pipe
When a liner fails to bond properly to the original pipe wall, it can separate, a defect known as delamination. This usually traces back to poor cleaning, incomplete resin saturation or incompatible materials. A delaminated liner can lose structural support, allow water to travel between the liner and host pipe, and in some cases deform or partially collapse inward. Proper preparation and correctly specified materials are the main defences against this.
7. Junctions Were Blocked or Badly Reinstated
When a liner is installed, it seals over every junction where a branch line connects into the main pipe. Those junctions then need to be reopened from inside the pipe using a robotic cutter guided by camera. If this step is rushed or done poorly, a junction can be left partially blocked, cut off-centre or damaged, restricting flow from that fixture even though the rest of the liner is perfectly sound. Junction reinstatement is one of the most skill-dependent parts of the whole job, and one of the places a poor installation most often shows itself.
What Happens if a Badly Collapsed Pipe Is Relined?
Sometimes the problem isn’t how the liner was installed, but the fact that relining was the wrong choice for that pipe. A liner relies on the host pipe keeping enough of its original shape to support it while it cures. If a section has collapsed or deformed badly, the liner may not sit correctly, may not make proper contact with the pipe wall, or may be asked to span a gap it was never designed to bridge. A thorough CCTV inspection before quoting is what identifies whether a pipe is genuinely suitable, or whether that section needs to be excavated and replaced instead.
How Does Post-Installation CCTV Identify Problems?
A follow-up CCTV inspection after the liner has cured is the single best quality check on a relining job. It allows the technician, and you, to see the finished work along its full length, confirming there are no significant wrinkles, voids, blisters or separation, and that every junction has been reopened cleanly. It catches workmanship problems while they can still be fixed under warranty, rather than leaving them to surface months later as a leak or a fresh blockage. The footage also gives you a clear record of the completed job for your files.
Can Failed Pipe Lining Be Repaired?
In many cases, yes. A localised defect, such as a badly reinstated junction or a short section with a resin void, can often be fixed with a targeted repair or a patch liner over the affected area. More widespread problems, such as significant delamination or extensive under-curing along the pipe, may require the failed liner to be cut out and the section relined again properly.
Does a Failed Reline Have to Be Excavated?
Not necessarily. Many failed liners can be removed and redone through the same access points used for the original job, without digging. Excavation becomes more likely when the host pipe itself has also failed, for example where a collapsed section was relined when it shouldn’t have been and the liner couldn’t support it. A CCTV inspection of the failed liner will show which situation you are dealing with.
How Can Homeowners Reduce the Risk Before Choosing a Provider?
Since almost every relining failure traces back to preparation and installation quality, the most effective way to protect yourself is to choose the right provider in the first place. Before accepting a quote, check that it includes:
- A CCTV inspection of your pipe before the quote is prepared
- High-pressure cleaning and any root cutting needed before installation
- The name of the liner and resin system, and confirmation it is WaterMark certified
- The number of junctions to be reinstated
- Post-installation CCTV footage of the finished work
- Product and workmanship warranties stated separately in writing
A provider who is confident in their process will answer every one of these points clearly and without hesitation.
Relining Done Properly Lasts
Pipe relining failures are real, but they are rarely random. They come from skipped cleaning, rushed resin work, poor curing control, unsuitable pipes or careless junction reinstatement. Choosing a provider who treats each of those steps seriously is what turns relining into the long-term fix it is meant to be.
King and Sons Plumbing carries out CCTV inspection before and after every relining job across Melbourne, with thorough pipe preparation, WaterMark-certified materials and written warranties on both product and workmanship. Call 03 9993 7122 to book an inspection or discuss your relining project.
