Can Reforming Fix Soft or Blistered Pitch Fibre Pipes?

Cost Effective Drainage Solution

Pitch fibre pipes remain a common feature in many UK homes, particularly those built between the nineteen fifties and the nineteen seventies. While they were once considered an innovative and cost effective drainage solution, time has shown that pitch fibre has significant limitations. One of the most frequent questions homeowners ask today is whether reforming can fix soft or blistered pitch fibre pipes. The answer is not always straightforward.

This article explains what pitch fibre pipes are, why they deteriorate, what reforming involves, and when it may or may not be an appropriate solution. The aim is to provide clear and impartial guidance so homeowners can make informed decisions about their drainage system.

What are pitch fibre pipes

Pitch fibre pipes are made from wood cellulose fibres bound together with coal tar pitch resin. They were widely used in post war Britain as a cheaper and lighter alternative to clay or cast iron pipes. At the time, pitch fibre was seen as a practical solution that allowed faster installation and reduced material costs.

Unfortunately, the organic nature of pitch fibre means it does not age well. Unlike clay or plastic, pitch fibre pipes are vulnerable to moisture, ground movement, and chemical exposure. Over time, these factors cause the material to lose strength and shape.

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Why pitch fibre pipes become soft or blistered

Softening and blistering are two of the most common signs of pitch fibre deterioration. Both occur as a result of prolonged exposure to moisture and waste water.

When pitch fibre absorbs water, the resin binding the fibres begins to weaken. This leads to softening of the pipe walls, making them more susceptible to deformation under pressure. In many cases, the pipe gradually loses its circular shape and begins to flatten.

Blistering occurs when layers of the pipe wall separate internally. Waste water can force its way between layers, creating raised bubbles or blisters on the inner surface of the pipe. These blisters reduce the internal diameter of the pipe and significantly increase the risk of blockages.

Common causes of pitch fibre drainage problems include long term water exposure, repeated blockages, root ingress placing pressure on weakened walls, ground movement, and age related material fatigue.

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What is pitch fibre reforming

Pitch fibre reforming is a repair technique designed to restore the original shape of deformed pipes. It does not replace the pipe or add a lining. Instead, it reshapes the existing pipe using specialist equipment.

The reforming process typically involves inserting a mechanical or hydraulic former into the affected section of pipe. This tool applies controlled pressure to push the pipe walls back into a more circular shape. In some cases, heat may also be used to soften the material slightly during the process.

Reforming is often considered because it is less invasive than full replacement and can be completed relatively quickly. However, it is important to understand its limitations.

Can reforming fix soft pitch fibre pipes

Reforming can sometimes improve the shape of soft pitch fibre pipes, but it does not reverse material degradation. If the pipe walls have become soft due to prolonged moisture exposure, reforming may temporarily restore flow but will not strengthen the pipe.

Soft pitch fibre remains structurally weak even after reforming. In practical terms, this means the pipe is likely to deform again over time, particularly if the underlying cause of moisture exposure is not resolved.

Reforming may be suitable in cases where softening is mild and deformation is minimal. It is more likely to be considered as a short to medium term measure rather than a permanent solutio

Can reforming fix blistered pitch fibre pipes

Blistered pitch fibre presents a greater challenge. Blistering indicates that the internal layers of the pipe have already separated. Reforming can sometimes reduce the size of blisters by flattening them against the pipe wall, but it cannot repair the underlying separation.

In many cases, blistered areas continue to deteriorate after reforming. Blisters may reappear or worsen, leading to renewed blockages and flow restrictions.

For this reason, reforming alone is rarely considered a long term fix for blistered pitch fibre pipes. It may be used as part of a broader repair strategy, but additional measures are often required.

When pitch fibre reforming may be suitable

Reforming may be considered appropriate when deformation is minor and the pipe walls still retain some structural integrity. It can also be useful where access for other repairs is limited or where a temporary improvement is required while longer term plans are made.

Situations where reforming may be suitable include early stage deformation without significant blistering, short sections of pipe affected rather than the entire run, and cases where a follow up repair such as lining is planned.

It is important to view reforming as a corrective technique rather than a cure. Its success depends heavily on the condition of the pipe at the time of repair.

Alternative solutions to pitch fibre reforming

CIPP lining

Cured in place pipe lining involves installing a resin impregnated liner inside the existing pipe. Once cured, the liner forms a new structural pipe within the old one. CIPP lining can seal blisters, reinforce weakened walls, and significantly extend the life of the drainage system.

This method is often considered the most effective non invasive solution for deteriorating pitch fibre pipes.

Pipe replacement

In cases of advanced deterioration, full replacement may be the only viable option. While more disruptive, replacement removes the problem entirely and allows modern materials to be installed.

The choice between lining and replacement depends on pipe condition, location, and overall system design.

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Conclusion

Reforming can sometimes improve the performance of soft or mildly deformed pitch fibre pipes, but it is not a universal solution. It does not repair blistering at a structural level and does not halt the ongoing deterioration of the material.

For homeowners facing pitch fibre drainage problems, the most important step is obtaining an accurate assessment through a CCTV drain survey. From there, the suitability of reforming, lining, or replacement can be considered based on evidence rather than assumption.

Understanding the limitations of reforming helps set realistic expectations and supports better long term decision making for the health of a property drainage system.

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