Gully replacement

Gully replacement is the removal of a defective surface water gully and installation of a new gully pot, trap and grating. Failure modes include cracked pots, lost or corroded gratings, sunken settings and broken connection collars to the outlet drain. A typical replacement involves opening the surrounding hard standing, lifting the old unit, bedding the new pot on concrete and reinstating the surface to match. Engineers should select a grating with the correct loading class under BS EN 124, especially where the gully is in a domestic driveway in a London terrace. Connection to the foul drain is not permitted under Building Regulations Part H, and the discharge must always be to a surface water drain or appropriate SuDS feature.