Is this ply board ok to tile onto?

[Element]

I haven't yet had a problem with tiling onto 18mm ply screwed comprehensively to either chipboard or wood floorboards; deflection can occur in such boards but when the load is spread with thick ply you'd really have to deliberately & aggresively jump up and down on the same spot to create a problem enough for a tile to come loose or crack... I've know floors that were tiled on 18mm ply 8 years ago without any obvious problem today...?

 

[jay]

End of the day its your call we can only recommend good luck

 

[Mike]

I haven't yet had a problem with tiling onto 18mm ply screwed comprehensively to either chipboard or wood floorboards; deflection can occur in such boards but when the load is spread with thick ply you'd really have to deliberately & aggresively jump up and down on the same spot to create a problem enough for a tile to come loose or crack... I've know floors that were tiled on 18mm ply 8 years ago without any obvious problem today...?

as said by joe (hillhead) a lot of ply is poor grade from china and is not suitable for tiling on. maybe it was better quality years ago or maybe you were lucky. the experts on here know what there talking about and you'll be taking a risk by not heeding there advice. good luck with it