Plastic Inspection Chambers ~ the raising piece can be sawn
horizontally with a carpenter's saw to suit depth requirements with
the cover and frame fitted at surface level. Bedding may be a
100 mm prepared shingle base or 150 mm wet concrete to ensure a
uniform support.The unit may need weighting to retain it in place in areas of high
water table, until backfilled with granular material. Under roads a
peripheral concrete collar is applied to the top of the chamber in
addition to the 150 mm thickness of concrete surrounding the
inspection chamber.Simple Drainage---Inspection Chambers