Floorboards…overboard and/or ditra?

[DJS]

hey there, long time no speak. I’m helping a friend tile their bathroom and they wish to waterproof the floor with an isolation membrane (ditra). Looking at the floorboards, I’m wondering if it would be advisable to overboard first with some cement/insulation boards?
Cheers

 

[Tile Marble Granite]

I would take the floorboards out and replace them with 18mm plywood. Uncoupling membrane on top. Send us some more pictures. Good luck!

 

[Dave]

hey there, long time no speak. I’m helping a friend tile their bathroom and they wish to waterproof the floor with an isolation membrane (ditra). Looking at the floorboards, I’m wondering if it would be advisable to overboard first with some cement/insulation boards?
Cheers

What is the reasoning for waterproofing? . Is it simply substrate protection? . Personally it seems it’s not a wetroom, so simply use 6mm hardibacker and tape the joints with hardibacker joint tape. Make sure floor boards are secured. That will suffice for any normal use bathroom floor.