Flooring under tile
I've read that you need 1 1/4" subfloor for large format tile. Can anyone clarify? I am not sure I understand the subfloor correctly.
The basement is unfinished and I can see the 2x8 joists 16" apart. On top of the joists are diagonally laid planks, which seem to be 3/4" thick. Are these diagonal planks calculated as part of the 1 1/4" subfloor? On top of the planks looks like 1/4" plywood (maybe 3/8"?), of which linoleum tiles are laid, adhered with black mastic. The tiles are perfectly flush with the surrounding hardwood.
In order to replace these tiles and meet the subfloor requirement for Large format porcelain tiles, is it correct to remove the linoleum (-1/8"),
add +1/4" of plywood
add +1/8" ditra uncoupling
add +1/4" tile?
Resulting in a 1/2" transition to the wood floors. Or do I need a thicker subfloor? Do I have to replace the plywood or planks?
The floors squeak but are not bouncy for normal walking. A heavy person jumping will cause a bounce.
Appreciate any recommendations for starting out.