It was decided to use Ditra Underlayment on this project because the wonderboard and heat system underlayment are only 1/4" and we didn't want to raise the floor much above the hardwood. The biggest mistake I made was to install the Ditra the next day after installing the heat system. The K/K was dry enough to walk on but not nearly totally dry. |
Ready to spread mortar for installing the Ditra. We plan on installing the Ditra under the cabinets as well.
The Ditra is installed and tiles helped keep the corners down. That's a problem with Ditra — the ends want to curl. Waterproof, but big deal. Water does not leak in the center of a floor, it would run around the sides and go down the wall. Another example of our industry creating a product and a selling point to deal with a problem that does not exist or not in play.
Luckly I didn't plan on installing the travertine floor next. I worked on the whirlpool and I realized that the K / K mortar under the Ditra was having a hard time drying because of Ditra being waterproof. So I cut some holes to help it out. Another big time problem for Ditra is they want you to use the cheapest mortar without additives, because of drying.
I decided to fill in the Ditra with mortar and let it dry. That way the tile setting mortar would have a space to dry under the tile into the dry mortar. Bottom line: It's not possible to do quality tile work using a mortar that mixes with water. There are many, many reasons, too numerous to mention here.
I used the flat side of the trowel and filled in the Ditra.
This was a good test: this tile didn't suit so I removed it the next day after installation. I really thought it would come up in one piece but I was wrong and the bond broke in the mortar as it should. The tile bonded and the mortar dried very well with only a small piece where it delaminated from the Ditra. So I felt good about the entire floor.
I also filled in the Ditra before installing bath floor. Normally I would use concrete board in baths that butt to hardwood but this one butt to carpet. Keeping the floor down for carpet and the threshold did not become a toe stomper.
Ditra is not going to keep me from using a quality setting mortar. Kerabond and Keralastic gives you a huge advantage in tile installations.