Self-leveling or MAPEI Planipatch under Ditra

Discussion in 'Floor Preparation' started by aresham, Jun 26, 2017.

  1. aresham

    aresham New Member

    Hi friends,
    Here is what I am dealing with. I have bump in the middle of the bathroom. and both side I have 1/8" to 7/32" that I need to fill to make it level. The floor is 3/4" Plywood and the tile would be 12X24". I have talked to Mapei and they told me that I shouldn't use self leveling, because it will crack under Ditra. They advise Planipatch. It doesn't sound right to me. what is your advise? Thanks.
  2. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    They don't give wrong advice that I've dealt with. Who did you speak to?

    Did you calculate deflection?

    Movement vertically will cause tile to crack, loose bond.

    Leveler may not bond well enough to proper exterior glue plywood.

    Me, I'd probably put down a layer of underlayment grade plywood(1/4",3/8") and then a vinyl/Duraceramic tile.

    So, I've heard a lot of crunchy ceramic tile in my days of removing. Self leveler upon drying creates tension, like you're causing me right now(playin) so as it is curing its very minutely shrinking. If it can't hold on to the substrate, it loses grip. It's usually mechanically assisted by wire lath fastened by galvanized nails in a 6" schedule have fun removing type fashion.
  3. The reason they stated that is that you're over a wood substrate. Self-leveling with cementitious patch is somewhat complicated to do over a wood subfloor. In most cases it requires the use of a metal lathe be used to counteract the movement of the wood subfloor.

    Ardex makes a product specifically for self-leveling over wood substrates and lightweight concrete called GS-4. This is a Portland cement-gypsum based self-leveling. This product doesn't require the use of a metal lathe. It would work to self level over a wood subfloor.

    Keep in mind you're adding a lot of weight to this structure with the self-leveling, mortar and tile. Depending on your joist spacing 3/4" subfloor may not be adequate. As Mike stated you should probably add a layer of 3/8" or 1/2" plywood over the subfloor to better support the weight.
  4. kylenelson

    kylenelson You'll find me on the floor I Support TFP Senior Member

    Planipatch is a junky patch, I wouldn't use it for anything you need to bond to it. It's chalky and just isn't up to par with most floor patch, and that is also reflected in its lower price

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