How hard could it be?
Updated: Dec 13, 2018
When it comes to tiling, the answer is HARD. Now I've tiled before, but I've never been responsible for a whole room. I was still pretty confident we could do this part too. I put a lot of research into what products we needed and how much. At one point we thought about putting in heated flooring but the cost didn't really justify it for us. One product we discovered during that process was Ditra Heat Duo (DHD), which we did end up using.
DHD is intended to be used on a floor where you are using heating cables and need a thermal break. On a concrete floor like ours, if you don't have a thermal break, when you're installing heating cables in the floor you end up losing a lot of heat to the slab and wasting energy basically heating the ground. DHD has a fleece-like backing that insulates the tile above from the ground below. The plastic grid on top of the fleece acts as a vapor barrier and uncoupling membrane, helping to keep your floor dry and keep your tile from cracking with movement in the subfloor.
Even without the heating cables, we wanted the benefit of insulting the floor so we wouldn't have frozen feet as well as the other benefits of Ditra. We ordered two rolls of DHD online which was enough for us to cover the floor in the whole room.
You have to install ditra over an unmodified thinset mortar both above and below the membrane. Ditra makes their own mortar, but we went with Mapei Kerabond mortar for under the ditra and Kerabond T (an unmodified thinset for large format tiles) over the ditra.
Mr. Handy and I went to Floor and Decor to pick up all the supplies thinking we could knock this out in a weekend (Ha!).
The only thing from that entire shopping trip that didn't weigh 50lbs was the 25lb bag of grout. This should have been the first sign that we might be in too deep! To be fair, Mr. Handy had been expressing doubts about whether we should be doing this part, but I have a strangely inflated sense of what we can do, so I was like, "pshhhhhhhhhh of course we can do this!"
We woke up the next day and got ready to tackle this floor. Started laying out the ditra and getting excited about the room coming together.
After we had all the pieces cut, it was time to start mixing up some mortar. Things were going so smoothly that I was actually believing we could get this done on the crazy time frame I had imagined! Then reality checked us. HARD.
Y'all. We followed all the instructions. Mix mortar, spread it out, trowel it lay ditra down, press it in, lift it up, check for coverage. That last step there: check for coverage. That is where it all went off the rails. The concrete floor was sucking up water from the moisture faster than we could get the ditra on it and making it hard to stick. It looked like it wasn't sticking at all! We fought our way through one row of ditra freaking out the whole time, sweating and cursing. One bucket of mortar down we decided we had to stop, regroup, and do some research about how it all had gone so wrong (in case you're curious, we needed to wet down the concrete first so it wouldn't suck all the moisture out. we had also been using the medium-bed Kerabond T which mixes up WAY thicker than a regular unmodified thinset. WHOOPS.). Even though we had theories on what went wrong and how to fix it we were still worried about messing it up even more. Memories of having the guys come fix the floor leveling came back to us... they were so fast... they carried all the heavy things...should we just try and finish the ditra and have them come do the tile? At the speed we were able to work, tiling was not going to happen until after thanksgiving and if we were lucky it would only take us a full weekend of work. We decided to just call the floor guy the next day to see what it would cost.
The next day we started to set up to try again with the underlayment. Mr. Handy casually commented, "what if we call them and they won't tile over our work?" And yet we kept setting up like we were going to continue. Then both of us snapped out of it and realized that we could prevent the very scenario we were worried about! We didn't have to keep going and hope they'd be able to work with our work. We stopped and decided to give them a call to find out how much it would cost for them to finish it ALL--- the ditra, the tile, the grout....all of it! We figured out our max we'd be willing to pay, gave them a call, and they came back well under our budget with a promise to fix whatever we might have messed up (within reason), lay the ditra, and do the tile with a timeline of 2 days. Needless to say, we agreed to this and regret nothing about handing this project to professionals.