Pig and Gorret are regional terms used to describe a deviance in level between the two skins of a cavity wall.
According to textbooks they should not occur, but in practice skins drift out of level, and the problem is known by many names in addition to the above!
Conventional roll DPC requires inner skin support at changes of level, abutments, and openings.
Consistent uniform and compliant protection is rarely possible if pigs and gorrets are present.
Approved Cavitrays by Cavity Trays of Yeovil are self-supporting.
At what height the inside skin coursing occurs makes no difference, plus Cavitray upstands are hinge-biased, to protect the as-found cavity dimension – consistent compatibility and conformity.
From the longest-established specialist.