Hello Im about to use Ditra for the first time and I was wondering if you could A. Recommend a brand name thin set motor to adheare the Ditra to my plywood floor and B. a product name to hold ceramic tile to the Ditra ? Thanks alot Tony

I personally use Mapei products for all my installations.

If Ditra is going over concrete I use Kerabond unmodified. If its over plywood or OSB then Ultraflex 2.

For setting over Ditra its always unmodified ( Kerabond for me)

Other products from Flextile, Custom or Tec will work. Just make sure they are the correct type.

From what I have read, it appears that ditra can be used over 5/8" subfloor instead of the 1 1/8 normaly required. Is this right?


Brent

Yes ... but you still need to make certain the deflection is not over L/360.
Ditra, as well as all cement boards offer no strength to the existing subfloor. Ditra prevents damage to a stone or tile installation by absorbing stresses caused by expansion and contraction. Deflection (up and down floor movements)can still cause damage ... even with Ditra.

The onus is always on the contractor or whomever is taking responsibility for the ceramic tile installation, to ensure the existing surface is solid and without deflection.

It is also very clear in the DITRA installation handbook, that the 5/8" plywood subfloor be TOUGUE AND GROOVE plywood. I have yet to come across a 5/8" plywood subfloor that meets that criteria.

I think you need to re-read the Schluter specs again.

All Schluter subfloor requirements refer to either OSB or plywood T&G.
5/8" subfloor single layer is acceptable under their 16" O.C. joist spacing specifications. It also depends whether your installing stone or ceramic/porcelain tile.

Indeed. There are a lot of misconceptions about DITRA and other crack isolation membranes. It's not a 'cure-all' for floors.

I've always joked that 5/8" T&G is the rarest construction product in the US. I have only seen it a few times, and that was years ago when I used to be able to buy fir plywood (very nice stuff BTW).

It's possible to get fir plywood here in Edmonton (Totem and Windsor Plywood), but it costs about double for the equivalent thickness in spruce. I usually use fir if I want a more ridgid plywood underlayment. There are a few small home builders in and around here that use 3/4 fir T&G as a subfloor and then 3/8 fir as a tile underlayment - nice floor for tile.

Robert, a lot of the time the wood we have available is from Canada. I don't know where that fir plywood was from but as I recall the upcharge over SYP was only about 25%.

Bri might remember this one....he called me one time on the cell while I was loading a truckload of material at HD. I noticed while I was loading that almost everything on my cart was stamped "made in Canada"...the plywood, the framing lumber, the dust masks, the glue, and even the sanding sheets for the orbital sander. I think the only non-Canadian product were some nails which were made in Tawain. LOL

Now if only I could just get some Tim's down here.