Two crews, one lift, no shared instruction
The practical issues between two contractors in a building are rarely about standards. They are about lifts, bin access, storage rooms, water points and the order in which floors are worked. Each crew has a route designed around its own scope, and neither has any visibility of the other's. Left to resolve itself, this produces a series of small frictions that arrive at the building manager as complaints about the other party.
None of that needs a contract between the contractors. It needs the building to state a few practical arrangements: which lift is used for equipment and when, where waste is consolidated, who has access to the service areas and at what times. Ten lines in a document removes almost all of it, and the building manager stops mediating a problem that was never about cleaning quality in the first place.
