Do I HAVE to use unmodified thinset over a Ditra membrane?
Think I'm beginning to understand this thinset modified/unmodified thing. We are DIY'ing our Master BR.
Both floor and shower walls will be 12 X 24 porcelain tiles.
We will be using Ditra on the floor, and Hydroban on the walls. Total square footage is ~135 sq ft.
My problem, and maybe it's not really a problem, is that I need to use modified thin set everywhere, except after I've installed the Ditra using modified, I am supposed to use unmodified to apply the tile. This floor area will only be about 35 sq ft. Am I being a cheapskate not wanting to buy another bag of mortar for this area, instead of using the modified I will already have? I will be buying 2 50 lb bags of the modified.
Guess I'm sort of talking myself into buying the extra bag even as I type this, but now am wondering why one is not supposed to use modified over the Ditra?
Anyways, if someone knowledgeable can enlighten me, that would be awesome!