I was fortunate to pick up a couple of free 50 lb bags of Mapei Novoplan 2 self leveling cement compound for free. I needed it to level the shower floor. Although some filling had been done with mortar, specifically a big hole in the corner near the wall, the Schluter Kerdi shower base installation requires a completely level floor.
I read the instructions on the Mapei website and then looked around the internet for installation advice and for my small area most of it didn’t pertain. Except I did decide to apply the Mapei primer. So I had to make a trip to buy that. For porous cement as in this shower which had never been sealed, the instructions recommended thinning the liquid 1:1 with water. So I did and spread it with a paint roller as recommended.
Some of the primer remained a bit white as it foamed a little when I mixed it with water. I tried to thin out the white areas but then I just left them and one coat seemed to dry very well giving a slightly shiny cast to the cement. The white spots went away after the primer dried overnight.
The next day I mixed the leveling cement. I had a partial bag to use up first. It was about 3/4 full so I used about a gallon of water instead of 5 quarts. It was easy to mix, pouring half of the bag into the pail of water and mixing with my good 1/2″ drill and cement paddle and then pouring the second half in and continuing to mix. The final product is quite soupy and I knew the consistency was right from watching videos of others pouring.
The advice was to mix the cement where you would be using it and I found out why when I carried that five gallon bucket into the bathroom from outside. Boy that was heavy.
The pour was pretty easy. I used a wooden float to smooth it out and push it together. The internet also said to keep the edges wet and mix and pour quickly. With such a small area that was no problem.
After pouring around the drain and getting it to flow evenly there, I poured the other end and worked it into the corners, then the pour met in the center. Unfortunately I only needed a little more than half of what I mixed. So a lot was wasted. I didn’t have another use for it so I just mixed water into it and dumped it on the outside gravel patio that we will eventually cover. The setup time was only 15 minutes and the slurry was workable most of that time. I tried smoothing a spot with a metal trowel but the cement just stuck to it and left a divot. In that one spot when I went back over with the wooden trowel I could tell it was starting to set so I just left it alone. The small divot the metal trowel made magically came back together through its self leveling power.
I didn’t try to alter the depth of the slurry, I just poured a bit and spread it around. I really wanted to maintain as deep a depression in the floor as possible so that the styrofoam Kerdi would meet the edge of the cut out in the cement. When pouring the floor I used some old panel doors from my daughter’s house to create the cut outs and those doors were just about the right depth for the Kerdi shower base.
Twenty four hours later I could have mortared in the Kerdi shower base but it took me awhile to cut the base to fit so that is the next job.