Pitch fibre pipes were first used for drainage in the UK in the 1950s, because they were cheaper than conventional fired clay pipes; their manufacture ceased in 1984. They are made of wood fibre impregnated with coal tar and are susceptible to delamination of their inner surface, tree root encroachment and damage from the passage of heavy vehicles.

Their average life is reckoned to be at best some 60 years, but the failures in these pipes have also been exacerbated by poor initial installation; unlike clay pipes, pitch fibre pipes require a granular bed and higher compaction and this was not fully realized before 1973!

So what happens is that pitch fibre pipes can become deformed over time, no longer keeping their round profile, looking more like a squashed sausage and causing frequent blockages and eventually total failure of the drainage system.

Where a building survey or an RICS Homebuyer service is being undertaken, Blocksaway Ltd. highly recommend the addition of a CCTV survey of the drainage before purchase, often at a cost of as little as £125; insurers are seeking to minimize their liability for pitch fibre drainage problems, and it is well worth establishing the condition and nature of pipework prior to purchasing a property.

Squashed pipe

Root ingress

Bulging drain causing frequent blockages