160mm Underground Drainage
160mm drainage pipe carries the flow from a larger building or a shared run where 110mm would surcharge. Pipe comes in 6m lengths with bends, junctions and reducers to step down into an existing system. For a house run, see 110mm underground drainage pipe.
Free delivery on orders over £150 inc VAT.
23 UK Branches
In Stock
Choosing 160mm Underground Drainage
Frequently Asked Questions
110mm covers almost every house run, foul and surface water alike. 160mm is for a larger building, a shared run serving several properties, or where an existing 160mm line has to be matched. Oversizing is not a safe default — a pipe running part full at low velocity is more likely to silt up.
As a general guide, a pipe under a garden or footpath is laid with at least 600mm of cover, and at least 900mm under a driveway or anywhere vehicles run. Shallower runs need protection such as a concrete surround. Depths, falls and bedding are covered by the Building Regulations, so confirm with building control before you backfill.
Granular material — pea shingle or similar — laid to an even bed so the pipe is supported along its whole length rather than bridging between high spots. Backfill in layers around and over it before any heavier material goes in. Pipe laid straight onto lumpy dug material is what cracks later under load.
With a flexible coupler sized to both outside diameters. Old clay, pitch fibre and cast iron were made to different sizes from modern plastic, so a straight socket will not seal. Measure the outside diameter of the existing pipe at a clean cut — not the bore — and match a coupler to that figure.