Can I lay STS backer boards over 6mm plywood?

[daveok77]

Hi everyone. DIYer here looking for some advice. Am tiling a bathroom floor and currently there is existing 6mm plywood well screwed into the floorboards. The floor itself (2.2m x 2.3m) is solid and there is no give in it. However, after reading through these forums, I am aware that I shouldn't be tiling over plywood, certainly not 6mm. My question is, can I lay 10mm STS backer board over the 6mm plywood and then lay my tiles?

Thanks

 

[Dave]

No. Remove the ply. Not a suitable base.