subfloor specs for ceramic tile

I am planning on laying ceramic tile in my kitchen. The floor specs are: 2x8 on 16" centers with a span of 10ft. The sub floor is 1x12 planks with about a 1/4" gap between them. On top the planks is a mix (about half and half) of 5/8" chip board and plywood (not t&g). The total measured thickness of the two layers is 1 3/8".

I was planning on using Ditra to keep the thickness to a minimum since I transition to a wood floor that is currently level with the subfloor.

Any advice is appreciated!

Scott

Under those circumstances your plan will work.

Hi Scott,

If the joists are in good condition your span is OK for tile installation. Your 1x12 planks will be OK too, just make sure they are well fastened and not cupped or warped. The 5/8" underlayment with no t&g does not create a problem either. But what you call "chip board" does.

Chip board refers to particle board, which is not a suitable product in a tile installation sandwich. You should remove it if it is particle board and replace it with an underlayment grade plywood, not CDX grade though. Due to variations in thickness you may want to remove all the underlayment and install new.

Ditra is my favorite membrane for a job like this, good choice.

Jaz

Chip board must be different where JAZ is. Here OSB is occaisionally referred to as chipboard. DITRA is legal over OSB.

Sorry about the confusion in terms but upon further review, what I have is NOT OSB but particle board as Jaz mentioned, so it doesn't sound like it is suitable for the floor. The joists and planks underneath are in good condition and very solid.

Just curious as to why the particle board doesn't work?

Scott

You may be right Bud. Chip board is what people have called particle board here since the '60's that I can recall. OSB is referred to as wafer board sometimes. Wafer because of the larger chips.

Too confusing. Just use plywood.

Simulcast. See, I was right!

Jaz