Why does Ditra have to be bonded to the floor? As I understand it, the purpose of Ditra is to uncouple the tile from the floor beneath it so each “layer” can move independently. If the sub-floor deflection is within acceptable limits, I don’t understand why cracks are more probable if the Ditra isn’t bonded to the floor.
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That waffle like texture is what gives it the cushion or..allows it to move w/o cracking the tiles. It sort of absorbs the movement I think.
ditra
ask Schluter who designed it
If it's not bonded you could lift an entire install up by just pulling up on one end. It's still decoupling the install because even with the bottom part bonded and the top attached to the tiles, the way it shifts laterally allows them to move around without the bottom changing. Think about two pieces of plywood with a bunch of springs between them. The top can move around a bit to the side without the bottom moving at all due to the springs.
I've done ditra only once. Listen when they say to go quite wet on that initial latex layer to the plywood/ditra connection. I went at the upper range of the latex mix and the install seems to be holding up fine, but you do want it quite wet to grab onto the bottom mat of the ditra properly.