Plumbers & electricians in North Tonbridge

Tonbridge once stopped at Cage Green. North of it there was little but fields and the road out to Shipbourne, and then, with housing in demand after the war, the town spread north in a run of estates, with York Parade built as their shopping street. Higham Wood and Trench Wood are the names most people give that newer housing, and the council wards that now cover the district, Higham, Trench, Cage Green and Angel, run from the edge of the older town out to where the houses give way to farmland.

What that leaves is a district of semis, short terraces and detached houses built to estate patterns, in brick, with gardens front and back and the drains running under the lawns and drives to a shared sewer in the road. The houses are sound and mostly unremarkable. The part nobody sees is what the drainage was made of, and on post-war estates that is not always clay.

That buried part is where this page goes.

Pitch fibre drains on the estates

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From about the nineteen fifties to the late seventies, a great many new estates were drained in pitch fibre pipe instead of salt glazed clay. It is made from wood or cellulose fibre, compressed and soaked in coal tar pitch, and to a builder laying hundreds of plots it had everything going for it: light enough to carry by hand, quick to cut and joint, and cheap. It has not aged well. Pitch fibre softens with age, and a pipe that has gone soft cannot hold its shape against the weight of the soil above it, so it slowly squashes from round to oval. The inside suffers too. Hot water from washing machines and dishwashers, along with fats and household detergents, attacks the inner layers, which lift away from the wall in bubbles and blisters and eventually peel into the bore. None of this happens at once. It creeps over decades, which is exactly why an estate laid in the sixties can go thirty years without a complaint and then start blocking in the forties and fifties of its life. Whether a particular TN10 house has it depends on who built that phase and when, and there is no way to tell from the front garden: the camera is the only honest test.

The householder rarely sees any of that. They see a kitchen sink that drains slowly, a toilet that needs two flushes, and a blockage that comes back a few weeks after it was rodded clear. Rodding pushes through the obstruction, but it cannot make a flattened pipe round again, and a blade or high pressure jet used carelessly can tear the softened wall and make things worse.

So the first job is a CCTV survey, and the report will usually say deformation, blistering or delamination with a percentage against each length. Where the pipe is still reasonably round, it can be re-rounded from the inside with a cutting head and then lined, which gives a new bore without digging. Where it has collapsed or deformed too far, that length has to be excavated and replaced in modern plastic. Which one applies depends on the camera, and it is common for one house to need both: a lined length under the drive and a dug-up length where the pipe has given way beneath a path. It is worth having the survey before agreeing to either.