OT: Ditra

[Michael]

A question about Ditra: I hesitate using it because it does not provide the stiffness of cement board that I would think would prevent failure. But everyone says it's wonderful. Should I not be worried about this?

Thanks!

[Markem618]

Installed right it give better performance than cement board alone, in a shower or wet floor area. Most Ditra installations that I have seen are over cement board though.

[Michael]

Ok, thanks! The instructional videos I have seen has the Ditra installed on the subfloor. I'll keep researching.

[Clare Snyder]

I have used ditra for tile flooring over plywood subfloor and it is GREAT. The purpose of Ditra is to uncouple the tile from the substrate. This allows the subfloor to expand and contract at a different rate than the tile from heat and humidity without cracking the tile or the grout line. Concrete backer board can NOT do this effectively - and nor can a mud bed.

[Michael]

Thanks! I guess I'm wondering about thicknesses. I learned that tile should be installed plywood + cement board to a thickness of 1 1/4 - 1 1/2. But 3/4 plywood + 1/8 Ditra + thinset is less than on inch. But that's enough to prevent floor flexing?

Appreciated!

[Clare Snyder]

3/4 inch fir ply on 16 inch centers is fine. Mine is 5/8" but the span is only 6 feet. I even use ditra on concrete to decouple the tile from any cracks that form in the concrete base.

[Michael]

Thanks! Much appreciated!