1/4” backer board or SLC under ditra?

[cnap]

Laying 3/8” porcelain tile and I need to bring a small section of the subfloor up 1/4”. It’s about 2’x16’. Basically I have a 1/4” discrepancy on the subfloor of a kitchen bump out and need to level off the existing (prior kitchen) lower section. Can I just build up the thinset in that area (1/4 plus the 1/8 that will be used on the other subfloor for the ditra)?

Or SLC to address the 1/4”? Or 1/4” backer board without thinset underneath (thinset and ditra on top). From what I’ve read I’m pretty sure plywood filler is a bad idea but wasn’t sure about backer board or just building it up with thinset since it’s only an extra 1/4”. Thanks.

Chase

[jadnashua]

DitraXL might give you enough extra height along with a slightly deeper notched trowel.

1/4” cbu , once you put the thin set under it and over it, will probably raise things a bit higher than you want.

What is the other surface you’re trying to match? If it’s wood, it’s fairly easy to make or have made a transition piece, or there are some profiles that can help if you like the look.

[cnap]

All of the tile will transition to a hardwood floor but the area with the 1/4” subfloor depth issue is under where the tile will go, so I’d prefer not to have transition between tile and another transition to hardwood.

I think your suggestion might work fine. Use ditra xl and a bit more thinset then transition to regular ditra. I should be able to also fudge a bit with this right at the transition point to ensure the tile is flat when setting it, right?

[jadnashua]

As long as you do not exceed the maximum depth of the thin set, a little more or less is usually okay. How deep the material you need for a particular installation depends on a few factors, mostly on how flat things are, both the back of the tile and the substrate. You need a complete coat and ideally, full coverage, and that requires at least some minimum thickness of the thin set material.