Floor construction - Ply, hardi or Wedi

[roswell]

Thank you for all the responses.

To summarise, the best option is to:

Use 18mm WBP ply (with underside and edges sealed - with what?) screwed down at 200mm centers. 2mm expansion joints between the staggered boards.
Then on top of the ply lay a 6mm cement board
Then complete with the UHF (200w mat), slc then adhesive and tiles.

Where would the decoupling membrane be installed?

Has nobody used or have any views on Wedi? Anyone?

Thank you
R

 

[grumpygrouter]

Thank you for all the responses.

To summarise, the best option is to:

Use 18mm WBP ply (with underside and edges sealed - with what?) screwed down at 200mm centers. 2mm expansion joints between the staggered boards.
Then on top of the ply lay a 6mm cement board
Then complete with the UHF (200w mat), slc then adhesive and tiles.

Where would the decoupling membrane be installed?

Has nobody used or have any views on Wedi? Anyone?

Thank you
R

I once saw an advertisement for one type of construction board showing a BMW X5 sat on a 50mm board supported at each end...can't remember which board though!! As to your question, I believe these types of board are designed as an insulating/backing layer prior to tiling and should be fixed to a full supporting surface to ensure stability. Never seen any manufacturers data sheets saying they can be laid straight onto joists!