Choice of pipe for area with subsidence - Soil/waste pipe

[Mac]

In our small estate we have 4 in pitch fibre pipes for foul drainage. A 10 m length under a lawn area needs replacing because it undulates and is flattened, probably due to subsidence apparent on the surface. This pipe serves six 2/3-bed houses.

Which type of pipe should we specify? Clay or plastic? 4 in or 6 in (or whatever the metric is)?

Cheers, Mac

[Tony McC]

Probably 110mm plastic. If it's laid with 150mm granular material all around, it can cope pretty well with minor ground movement.

[GB_Groundworks]

current reg say you are not allowed to change diameter in the run only in inspection chambers but you should be fine on a repair if you are worried about it happening again specify ultra rib 110mm and as tony say make sure its bedded correctly

[lutonlagerlout]

we have found pitch fibre before all egg shaped
biggest problem is connecting your nice round 110 mm pipes to the egg shaped pitch fibre
LLL

[flowjoe]

Pitch fibre is known for becoming mishaped and blistered regardless of ground movement, a very poor product all round.

Speak to your insurers, the ombudsman ruled some time back that insurers should be picking up the bill for this kind of work.

[Tony McC]

....but at the time, before the advent of uPVC pipes, pitch fibre was seen as revolutionary because is was cheap and light and easy to cut...all the things salt-glazed clayware wasn't.

The easiest way to replace a 10m run, bearing in mind the deformation that LLL mentions, is to build a new IC at each end, but it would be a better job to replace the entire run, rather than do it piecemeal.

[rab1]

showing your age there boss