How much movement is acceptable for a wall hung toilet?

[MattW1960]

I'm a home inspector in NYC and I see a few wall-hung toilets every month. I put my knee on the toilet to see if there's movement under weight and sometimes there is visible movement separation between the top of the bowl and the wall. Usually the movement amounts to the thickness of a few sheets of paper. How much movement would you professionals consider to be "acceptable" before there is risk of eventual compromise of the drain connection?

-Matt

 

[arctic bill]

none, when i was an inspector i wanted the supporting wall made out of 2x6 . if there is movement the seal will leak .