Manhole Units - Soakaways

Manhole Rings

Soakaway sections can be installed individually or by combining several together to provide sufficient storage and area of exfiltration. The effective storage capacity should be calculated using the depth of chamber below the invert of the incoming pipe and the base of the chamber or the top of the water table whichever is the highest.

Soakaways are being used increasingly as part of SUDS schemes with new building works in urban areas, as a sustainable way of dealing with rainwater and surface water runoff, and to avoid the costs of sewer upgrading.

BS EN 752: PE 1-4: 1996-98 recommends in ground with low permeability, the storage capacity should equal 12mm of rainfall over the area to be drained.

In suitable ground conditions the soakaway can be placed on a ring strip foundation thus providing additional exfiltration through the base of the chamber. If ground heave cannot be ruled out, the units should be sited on a concrete foundation slab. The excavation should be backfilled with a band of 40mm nominal single size stone, stone rejects or hardcore to provide permeable surround to the soakaway chamber.

It is recommended that soakaways should be constructed not less than approximately 5m from a building or in a position where the ground below the foundations is likely to be adversely affected.

To view our sizes and availability of soakways click here.