Twinsprings Research Institute

Before tackling the tile in the master bath I put the thin Schluter membrane over the foam edges of the floor. This is installed with unmodified mortar. The east side strip is narrow because we used 1.5″ polyiso over the concrete foundation to hold in more heat.

Narrow edge treatment

The plan for the master bath tile is to finish under and behind the tub and the faucet step. Then after putting the tub in place the toilet and sink side can be tiled. With the tub about in the middle of the room there was enough space for two rows of tile.

Two tiles wide behind tub

With only two rows of tile I would end up trying to tile and grout under the bathroom edge of the tub. That would not work very well. Instead we moved the tub as far as we could toward the sink and toilet side and added another row of tile so that the tub will sit on three rows of grouted tile and completely cover under the tub.

Three tiles wide under tub

I screwed the stand pipes for the freestanding faucet through the plywood cover of the plumbing step. The seem to fit well. I have to remember to put on the connector and the floor flange when they are installed.

Freestanding faucet on step

I started tiling the wall even though the third row of floor tile wasn’t dry. I decided to glue the tile to the wall with tile adhesive as it is very sticky and does not slide down like mortar can. The adhesive recommended using up to 6 inch tiles but it is possible to use with up to 13 inch tiles if more time is given to dry before grouting. The adhesive dries slowly and the middle of larger tiles don’t get enough air to dry quickly.

Tiling the wall behind the tub

I tried to square and level the rows of tile but didn’t get them exactly straight. Most of this wall is hidden behind the tub so I’m not going to worry about it.

There are only a few boxes of edge tiles but I decided to use them on the step to overlap the tile on the sides and create a more finished edge for the step. It was also easier to cut holes for the stand pipes in the narrower tiles as all the holes were at the edges of the tiles.

Tiled step

Cutting tile for the step took far longer than laying the tile on the floor and the wall. The job is a bit sloppy but after grouting it should look fine.

Back wall and step

After cleaning two times with the Spectralock solution and once with a vinegar solution, the wall, floor, and step are looking pretty good.

Step nearly finished–need to complete the back side.

Now this side of the bathroom is finished and ready for the oak beam shelf to get installed. Then the tub can be moved and the drain connected.

Back wall finished

Spectralock Contents

Epoxy grout has several advantages over cement grout. It is stain proof, the colors are consistent, the grout is crack resistant, and it is easier to clean than cement grout. Its disadvantages are that it is expensive and gives limited time to work before it sets up especially in warm weather.

My brother used epoxy grout in his shower and he thought it was great stuff. I needed grout that was resistant to cracking especially for the tile on the perimeter of the slab where it is over foam insulation.

I purchased 500 square ft of brown porcelain tile through a craigslist ad and I figured that the commercial size of Spectralock grout would be adequate if I used it all. These boxes contain four full sets of part A and B and four containers of the fine colored sand used in the grout mix.

Because the epoxy grout sets up so quickly, a beginner definitely needs to mix only a small amount at one time. The Laticrete site has a spreadsheet calculator for various sized tiles and grout lines. I downloaded it and a full unit of Spectralock Pro would cover about 176 square ft of 1/8″ grout lines for 13″ x 13″ tile. A mini unit of grout covers about 44 square ft. which is perfect for the bathroom.

I found a website that explained how to split a full unit into four mini units. So that is what I did. It was important to weigh the material to ensure an exact amount of each part. I used our kitchen scale.

Spectralock Part A

The epoxy parts are not easy to work with as they are sticky and don’t ooze out of the packets that easily, especially part B.

Spectralock Part B

The grout is sanded but the sand used is very fine. It is combined with the color in an exact mix so that from batch to batch the color is consistent.

Spectralock Part C

After dividing the full unit into three smaller parts to keep and one to use which I left in the original packages, I was able to mix Part A and Part B from what was left and then add Part C, the sandy part. The website that I read said to mix well only about 75% of the dry sand and then add the remainder to get the final consistency.

Mixed Epoxy Grout

The mix seemed on the dry side so I didn’t use all the Part C. But I used most of it. The texture is supposed to be like peanut butter but mine was a little stiffer. The instructions say to dump it all out on the tile but I thought that would be difficult to move around, also it is supposed to be applied with the rubber grout float but I found I could squish it into the grout gaps easier with a trowel and then cleaned the excess off with the rubber float.

After the grout lines are filled, it is a 15 minute wait to wipe off the excess. Another way to measure is from the time the process started, so the first wash should be within an hour of mixing the grout. The wait time is longer if it is colder, but these days are warm at 85-90 degrees so I waited about 10 minutes and started the first wash. I used the included cleaner for the first wash but instead of using a sponge, I used a blue microfiber pad. It was easier to rinse out often and I could feel the excess grout through the pad when I could not feel it through the sponge.

First Wash

During this wash the grout is still malleable and if there is a gap in the lines extra grout scraped from the tile or from the original mix can be pressed into the empty spaces. I just did this with my fingers and then wiped the grout line to make it look even.

This is the grout that was left over after I finished the tile. I just discarded it. The instructions say to count on at least 10% waste and that looked about what I had left over.

Left over epoxy grout

I cleaned the floor the second time with just vinegar and water and a white 3M pad which scraped off the grout that stuck to the tile followed by wiping with the microfiber pad. I had to rinse the pad often and I felt it start to get gummy before I was finished. When a sponge gets gummy they say to throw it away and use a clean one, but I was able to soak the pad in a bucket of vinegar and warm water and the gumminess rinsed away.
I used the sponge on the final vinegar and warm water rinse instead of the pad and the water stayed very clean, one of the ways I could tell it was finished. The floor looked great without any epoxy haze left on the tile.

After third rinse

Guest bath toilet

I’ve decided to lay the floor tile before reinstalling the family room bathroom toilet and sink. I don’t really want to install them and then later take them out again to tile. Why not tile first? The question was whether to use an underlayment on the concrete or not. Ordering the substrate delays starting the project and adds extra cost.

That bathroom floor has several cracks in it. I’m not sure whether the bigger shower and its thinner concrete has caused more cracking or if it is just a weak area for some other reason. In the upper right corner I have one of the tiles I am using laid out. It is hard to tell it from the stained concrete floor.

Bathroom Floor Cracks

There is even a crack that went through the base of the toilet when it was installed before the walls were up or drywalled. We took it out to finish the drywall.

Toilet Base Crack

The toilet crack made me believe that if the floor continues to crack, the tile will also crack. I’m using Schluter products in the showers and it seems like a good preventative to use the Ditra uncoupling membrane on this bathroom floor.
This layer is mortared into place first before the tile is set. The Schluter site explains how the membrane works to minimize or eliminate cracking even on OSB plywood.

DITRA provides uncoupling through its open rib structure, which allows for in-plane movement that effectively neutralizes the differential movement stresses between the substrate and the tile, thus eliminating the major cause of cracking and delaminating of the tiled surface.

I chose to order the Ditra through an ebay site because it appeared to be the most convenient way to get it, although it is about the same cost at our local big box store, It is not in stock and would have to be shipped to the store. Big box stores take as long or longer to ship to store or home as online stores.

Ditra Underlayment