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Pitch Fibre Pipes: The Hidden Risks Lurking Beneath our Feet

Pitch fibre pipes, once heralded as the innovative and cost-effective choice for drainage systems in the UK, have aged poorly and are now a significant cause for concern.

First introduced in the 1950s and widely used through the 1960s and 1970s, these pipes were initially favoured for their affordability, ease of installation, and lightweight design. We have seen a lot of these types of pipes when unblocking drains in Newcastle.

However, as time passed, the problems associated with pitch fibre pipes became apparent, and they are now considered a ticking time bomb for drainage systems.

This article will explore the most common issues related to pitch fibre pipes and the solutions available to address these problems.

  1. Deformation and Collapsing

One of the primary issues associated with pitch fibre pipes is deformation or warping. As the pipes age, they lose their structural integrity, making them susceptible to external pressure from soil or groundwater. This can lead to an oval-shaped deformation, commonly referred to as ‘egg-shaping,’ which reduces the flow capacity of the pipe, causing blockages and potential collapse.

  1. Blistering and Delamination

Over time, pitch fibre pipes can suffer from a phenomenon known as blistering. The pitch fibre material begins to separate from the internal pipe wall, creating bubbles or blisters that fill with water or sewage. This weakens the pipe structure and narrows the internal diameter, leading to blockages and potential sewage backup.

  1. Infiltration and Exfiltration

The ageing process of pitch fibre pipes can result in small cracks and fractures in the pipe walls. These cracks can allow groundwater to infiltrate the drainage system, causing overloading and reduced efficiency. Conversely, cracks can also lead to exfiltration, where sewage escapes the pipe and contaminates the surrounding soil and groundwater. This poses a significant risk to the environment and public health.

  1. Tree Root Intrusion

The deteriorating condition of pitch fibre pipes can make them attractive to tree roots, which are drawn to the moisture and nutrients found in sewage. Once a root penetrates a pipe, it can continue to grow and expand, leading to further damage and blockages within the drainage system.

Pitch Fibre Pipe Solutions and Recommendations

While the problems associated with pitch fibre pipes can be severe, there are several options available to address them:

  1. Pipe Relining: This method involves inserting a new liner into the existing pipe, which is then cured using heat or UV light. This effectively creates a new, more durable pipe within the old one, restoring its structural integrity and flow capacity.
  2. Pipe Bursting: A technique designed to replace a damaged pipe entirely. A bursting head is pulled through the existing pipe, breaking it apart and simultaneously pulling a new pipe into place.
  3. Excavation and Replacement: In some cases, the best solution may be to excavate and replace the damaged pitch fibre pipe with a more modern and durable material, such as PVC or high-density polyethylene (HDPE).


The problems caused by pitch fibre pipes pose significant risks to property owners, the environment, and public health. As these pipes continue to age, assessing their condition and taking appropriate action becomes increasingly important. By exploring the available solutions and working with experienced drainage professionals, property owners can mitigate the risks associated with pitch fibre pipes and protect their investment for years to come.

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