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Why pitch fibre pipes cause so many problems

| Gerry Rowe

An image of pitch fibre pipes. It's hard to tell you have pitch fibre pipes until the problems begin.
An image of pitch fibre pipes. It's hard to tell you have pitch fibre pipes until the problems begin.

You do not know you have pitch fibre pipes until years later, when the trouble starts.

This has been seen many times. Someone calls ASL Limited because they have had two or three blocked drains in the last year. A different company each time. The drain is rodded, maybe jetted, maybe even tankered. Each time, the customer thinks, “Right, that should sort it.” It keeps coming back. That is when we start asking questions.

Start with this simple test

If you have had more than one blocked drain in a year, it is time to ask why this keeps happening. Normal drains should not do that, even if you have a big household. If your drainage person has not brought up pitch fibre pipes, they might not be looking for it. Not all drainage people are the same. Some do not have the experience, and you need experience to spot pitch fibre.

Here is why it is so hard to spot

Pitch fibre pipes are black, shiny-looking, and bendy when new, but over time, they soften, blister, and collapse. On camera, they can look a bit like normal plastic pipes if you are not careful. But they are not. They are made from compressed coal tar and wood fibre, and they were cheap, so builders used them right through the 1960s, 1970s, and even into the 1980s. Sometimes, we have to poke them with a screwdriver to confirm they are pitch fibre. That is how soft they get. Once they start sagging or blistering inside, water and waste get trapped, and blockages form. Jetting helps for a while, but eventually, it clogs again.

What usually happens next

The ASL teams on site attending to a repair of pitch fibre pipes. The tank had to be emptied in order to drain down the system and fix the problem.
The ASL teams on site attending to a repair of pitch fibre pipes. The tank had to be emptied in order to drain down the system and fix the problem.

If no one identifies the real problem, here is how it plays out:

  1. Jetting does not clear it properly
  2. A tanker gets called to suck everything out
  3. Someone finally sends in a camera
  4. That is when you hear it: “Ahhh, that is pitch fibre. That is why it keeps happening.”

This situation is familiar to us at ASL Limited.

ASL Limited always checks for pitch fibre because it is common in our area

We work around Guildford, Woking, Haslemere, Cranleigh, and all across Surrey. Pitch fibre is still everywhere. It is one of the first things we look for because it causes so much confusion. The sooner it is identified, the easier the fix.

Not every drainage company has the right gear

Re-rounding pitch fibre is a specialist job. Proper re-rounding equipment is needed, with tools that reshape the pipe from inside to restore its diameter. This is not DIY or guesswork. It is a professional fix that avoids digging up the whole garden or drive. If the pipe is too far gone, we also offer structural lining. If it can be re-rounded, we can build a new pipe inside the old one, with no digging at all.

You are not imagining it, something is wrong

If you have had multiple blocked drains in a short space of time, jetting that only helps for a few weeks, tanker callouts with no clear answer, and no one has mentioned pitch fibre, then you might be dealing with pitch fibre pipework. It is time to get a proper investigation done.

If you have had enough of mystery blockages, read about blocked drain clearance.

Think you might have pitch fibre drains?

Call ASL Limited on 0800 181 684. The cause will be found and fixed for good.

We cover Surrey, Berkshire, Hampshire, West Sussex and South West London.

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Need advice or support?

📞 Call ASL Limited on 0800 181 684 – we're always here to help.

🔗 email us at info@asllimited.co.uk – no obligation, just guidance.

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We cover Surrey, Berkshire, Hampshire, West Sussex and South West London.

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