What are pitch fibre drains?
Pitch fibre is common amongst building work done around the 1960’s and 1970’s. Most pitch fibre has reached the end of its useful lifetime by now. Pitch fibre typically squashes and bubbles which prevents flow of solids. The blisters in the pipe and the squashing can get so severe that the drain camera cannot pass through the pipe. This would mean the pipe is roughly 50% squashed and delaminated.
Pitch fibre drains can be found by using our CCTV camera's after a blockage or with a CCTV survey.
How do we repair pitch fibre drains?
We can, in some cases, re-round the old squashed and bubbled pitch fibre without digging by using our re-rounding equipment. It is vital to do this work before the pitch fibre drains become too bubbled or squashed as re-rounding will only work to a certain point of pipe disrepair.
If the pitch fibre pipe has not degraded too badly then we can re-round the pipe which involves putting a heavy winched re-rounder through the pipe which forces the pipe out to the open position and removes any bubbling on the inside. Various grades of re-rounder are winched through the drain until the drain is back to roughly 95% of the original circular diameter. Afterwards a set of metal brushes are sent through the pipe to clean the pitch fibre of the small lumps and debris from the re-rounding process. Once the pipe has been re-rounded and cleaned we install our liner (please see lining and patch lining page) to structurally secure the now circular but weakened pitch fibre pipe.
All of this is done without the need to excavate. We can re-round, clean and line the pitch fibre drain from the manholes.
If the pitch fibre has degraded too badly then the pipe may not be able to be re-rounded and lined and a a section may need to be excavated (please see excavation and drain replacement page) in conjunction.
How long will the repair last?
Once the pipe has been re-rounded and lined you won't have to worry about your drains again. Our lining material exceeds WRc criteria and provides a 50-year design life with a safety factor of 2, effectively giving one hundred years’ life expectancy.