I have an ACO drain on new build (7 year old), the drive keeps sinking in one corner, most recently repaired by setting the outage edge in a motar bed. Aco drain is solid, looks to have been laid on concrete and haunched. Looking for a reasonably permanent fix without needing to lift the drive / ACO. I was thinking of buying a 110mm insert for the pipe to bridge the gap, tidying up the opening so it fits around the insert and using a flexible waterproof filler around that. Any better ideas / products? (DIYable, success measured by not having to fix the drive every 3 months….
