Tiling over floorboards

[epymsam]

I've a victorian cottage and I want to tile the bathroom floor which currently has exposed floorboards. These have been previously gap-filled and sealed. Can I use ditra matting on this substrate or is it a case of replacing the boards with 15mm marine ply? I don't think its feasible to add ply on top as this will leave a 25mm plus step into the bathroom.

Your advice would be greatly appreviated.

Thanks

 

[epymsam]

Just a note, the floorboards are not tongue and groove, just pine planks, so there is probably more independent movement when compared to T&G boards.

 

[Concept PHT]

Hi there,

I would always lay ply on top of new or old boards, seal/tank as required and crack on with the tiling from there.

Other than that, lift the floorboards and re lay with new t&g, making sure they are well in place and crack on with the sealing etc... Bit of a task though