How Resin Relining Extends the Life of Pitch Fibre Drainage Pipes

What Are Pitch Fibre Pipes?

Pitch fibre pipes are made from wood cellulose fibres that are mixed with coal tar pitch and then compressed into a lightweight, flexible drainage pipe. At the time of production, these pipes offered several advantages: they were cheaper than traditional materials, easy to transport, and simple to install. Their flexibility also meant they were less likely to crack during ground movement.

Unfortunately, this combination of materials does not age well. Pitch fibre softens over time when exposed to moisture, heat, and constant pressure from soil and waste. The material becomes weaker, more brittle, and more prone to distortion. As the decades pass, homeowners with original pitch fibre pipes often begin to notice drainage problems that gradually worsen if left untreated.

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Common Problems With Pitch Fibre Drainage Pipes

One of the most common issues is blistering. As water and waste travel through the pipe, moisture soaks into the material and causes the inner surface to bubble and swell. These blisters protrude into the pipe’s interior, creating rough surfaces that slow the flow of waste and allow debris to accumulate. Over time, this leads to repeated blockages.

Delamination is another frequent problem. Pitch fibre pipes are made from layers of compressed material, and those layers can begin to peel apart after decades of use. Once delamination begins, the structure of the pipe becomes significantly weaker. The internal surface becomes uneven and can trap anything from toilet paper to larger debris, making the system more prone to failure.

Deformation is also very common. As soil presses against the weakened pipe, it can lose its round shape and become flattened or misshapen. This not only affects water flow but also increases the pressure on already fragile pipe walls. Left untreated, deformation can eventually lead to a complete or partial collapse.

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Signs Your Pitch Fibre Pipes May Need Resin Relining

Homeowners often first notice problems through symptoms rather than visible damage. Recurring blockages are among the earliest warning signs, especially when they keep returning despite attempts to clear them. Slow-draining sinks, baths, or toilets may indicate a restriction caused by blistering or deformation within the pipe. Unpleasant smells around the home or garden can signal that waste is not flowing properly or that water is sitting stagnant inside a distorted pipe. Gurgling sounds coming from the plumbing system may also indicate air pockets caused by narrowing or collapsing pipework.

On the surface, you may notice water pooling around gullies or manhole covers, suggesting that waste is not reaching the main sewer line effectively. Ultimately, the most reliable way to confirm any suspicion is through a CCTV drain survey, which provides clear visibility inside the pipe and confirms whether resin relining is necessary.

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What Is Resin Relining?

Resin relining is a modern, trenchless technique designed to restore damaged drainage pipes without digging them up. Instead of excavating the surrounding ground, specialists install a new pipe liner inside the original pitch fibre pipe. This liner is coated with a powerful resin that hardens into a strong, long-lasting material, essentially creating a new pipe within the old one.

This method not only repairs structural weaknesses but also reinforces the pipe so that it becomes resistant to future problems. Resin relining is particularly beneficial for homeowners on the South Coast who want to avoid disruption to landscaped gardens, paved areas, or driveways.

How Resin Relining Works: Step-by-Step

The process begins with a CCTV inspection. Technicians use a high-definition drain camera to examine the internal condition of the pipe. This inspection reveals the extent of blistering, deformation, blockages, and any areas that may be at risk of collapse.

Once the inspection is complete, the pipe must be thoroughly cleaned. High-pressure water jetting or mechanical cutting tools remove debris, old pitch fibre layers, grease, and any loose material that could prevent the liner from bonding properly to the inside of the pipe. This cleaning stage is essential for ensuring that the new liner adheres correctly and forms a smooth, uniform surface.

After the cleaning, the liner is prepared. This liner is usually a flexible tube made from felt or fibreglass, which is saturated with a specially formulated resin.

The liner is then inserted into the existing pipe. This is typically done using air or water pressure to invert or pull the liner through the pipework. As the liner moves into place, it expands and presses firmly against the weakened walls of the pitch fibre pipe.

The next stage is curing. Depending on the system used, the resin may harden naturally at room temperature, or it may be accelerated using hot water or UV light. Once the resin has cured, it forms a new, solid, watertight pipe within the original structure.

Finally, the system is inspected again using CCTV to ensure that the relining has been successful.

How Resin Relining Extends the Life of Pitch Fibre Pipes

Resin relining significantly strengthens the existing pipe by providing a new structural layer that no longer relies on the weakened pitch fibre itself. Once the liner has cured, it prevents further blistering, delamination, and deformation because the original pipe is no longer in direct contact with flowing water or waste.

The new internal surface is extremely smooth, which improves water flow and reduces the likelihood of future blockages. It also seals any cracks or gaps and prevents tree roots from entering the pipework. As a result, the drainage system becomes more stable, more efficient, and much less susceptible to future damage.

By reinforcing the pipe from within, relining essentially gives the drainage system a brand-new structural lifespan, even if the original pitch fibre pipe has begun to deteriorate.

How Long Does Resin Relining Last?

Modern resin liners are designed to last between forty and fifty years at a minimum, and some studies suggest they may last even longer based on accelerated ageing tests. In comparison, the original pitch fibre pipes were only ever expected to last around thirty to forty years, and many installations are now long past that point.

This significant difference in lifespan is one of the main reasons why resin relining is such a popular choice for homeowners across the South Coast. It provides a long-term solution that is durable, reliable, and cost-effective.

Advantages of Resin Relining

The biggest advantage of resin relining is that it restores strength to the drainage system without excavation. It prevents further deterioration by forming a rigid, watertight pipe that is resistant to cracking, blistering, and deformation. The smoother internal surface allows waste to flow more freely, reducing the likelihood of future blockages. Resin relining is also more environmentally friendly because it avoids the need to remove and dispose of large sections of pipework.

For many homeowners, especially those with gardens, patios, or driveways they want to preserve, the ability to repair a drainage system without digging is a major benefit. Combined with its long lifespan, resin relining is often the preferred approach to repairing pitch fibre drains.