Pitch Fibre Drain Repair
pitch fibre repair
If your drain blocks again a few weeks after it was last cleared, and the house went up between about 1950 and the early 1970s, the pipe itself is very likely the problem rather than what is going down it.
Pitch fibre — wood pulp soaked in bitumen — was laid across post-war Britain in enormous quantities. It was designed to last around forty years. Most of what is still in the ground is now sixty to eighty years old, and it does not fail cleanly. It sags, blisters and loses its shape along a whole length, so jetting buys a few weeks and the problem comes straight back.
Exjet has been repairing and replacing pitch fibre drains across the South West since 1986.
Survey First
Measuring the Problem
We put a camera down and record what is actually there: the material, how far the pipe has deformed as a percentage of its original diameter, and where the blistering and delamination sit along the run.
A quote built on “there is pitch fibre in the garden” is guesswork. A quote built on a measured survey is a plan — and it is the difference between lining a drain and digging up a driveway that did not need to come up.
Where the Defect Sits
We also record whether the defect falls inside or outside your boundary. On post-war estates that single fact can change who pays for the work, and it is covered further down this page.
Rerounding and Lining
How It Works
Where the pipe has deformed but is otherwise sound, we winch a rerounding tool through it to force the bore back to a circular section, then install a cured-in-place liner immediately behind it. The liner sets hard and holds the new shape permanently.
Done properly you get a new structural pipe inside the old one, with no excavation, no digging up the drive and no reinstatement bill.
Why Both Steps Matter
Pitch fibre has a memory. Reround it and leave it, and it creeps back to oval within weeks. Anyone quoting to reround without lining is selling a repair that will not see out the year.
Excavation and Replacement
When Lining Will Not Hold
Lining has limits, and we will tell you when you have reached them. We excavate and replace where the pipe has collapsed or a section is missing, where deformation is too severe to reround without splitting, where joints have moved too far for a liner to seal across, or where the line needs re-routing or the gradient is wrong.
The Ten-Year View
Replacement is more disruptive and it costs more. On a badly gone run it is also the cheaper answer over ten years, and we would rather say so at the survey than halfway through a failed lining job.
Part of the Pipe May Not Be Yours
Since 1 October 2011, most lateral drains beyond the property boundary and most shared drains serving several houses transferred to the water companies. Post-war estates are exactly where pitch fibre was laid, and exactly where drains were built to serve rows of houses.
So a survey that establishes where the defect sits relative to your boundary can be the difference between your bill and the water company’s. It is not automatic and they will want evidence — which is another reason the survey comes first.
Book a Pitch Fibre Survey
We survey, reround, line and excavate with our own directly employed engineers, so the recommendation you get is based on what the pipe needs rather than what happens to be on the van. Certified to ISO 9001, ISO 14001 and ISO 45001, and working across Devon, Cornwall, Somerset and Dorset since 1986.
Ring 0800 328 6655 — answered any hour.