ABOVE: Misting the walls prior to applying thinset. I thoroughly mist the walls, then I mix the thinset. While the thinset is slaking, I cut my Kerdi to size, then lightly mist the wall a second time.

ABOVE: Working quickly, I flat trowel the thinset on the wall, using my Sharpie marks as a guide. I work bottom-to-top, as I find the incandescent lighting can accelerate the thinset skinning over.

ABOVE: Once flat troweling is done, I comb the thinset with the notched edge of the trowel, again working bottom-to-top.

ABOVE: I quickly get the Kerdi over the combed thinset, I hold it plumb, then lightly run my hands across the top of the sheet, then down the middle of the sheet. Just enough to adhere it to the thinset. I then work top-to-bottom and run my hands from the center of the sheet to the edges, lightly bedding the Kerdi in the thinset.

ABOVE: Kerdi is bright orange. Once it's bedded in the thinnset, it turns a muddied brownish-orange. After hand setting the sheet, I use a 4" taping knife to thoroughly embed the Kerdi in the thinset. I run the knife at a low angle, with a bit of pressure, working in the same manner that I initially set it with my hands...top-to-bottom, and center-to-edges.

ABOVE: Process repeated for second sheet. Kerdi has printed lines 2" (50mm) from the edge of the membrane to assist in getting the proper overlap. this shot shows the second sheet going up, you can see the sheet going from bright orange to muddied orange as I work it into the thinset.

ABOVE: This bright orange spot indicates no thinset behind this part of membrane. I'll use the taping knife to draw some thinset from adjacent areas to this spot.

ABOVE: Setting a plumb line to hang the first sheet. Just like hanging wall paper. I hold the first sheet about an inch from the inside corner. Sheet is about 39-1/2" wide. I want the thinset to extend about 1" past the edge of the sheet. So I drop a plumb line about 41-1/2" or so from the inside corner, and mark the line vertically every foot or so with a tick mark using a sharpie.

ABOVE: Thinset. This is a little thicker than I want. I want it stiff enough so I can flat trowel it on the wall without it dripping all over or running down the wall, as well as it being able to hold a ridge after it's combed out. Not too stiff, though as you don't want it skinning over before you hang the sheet.

There are ways and there are ways. This post shows a couple of ways to do it.

Shower is a walk-in, about 5' by 7'. Door is at a 45 degree angle.

Walk in to the shower and on the short wall to the immediate right are two supply valves, the lower one supplies the wall mounted handheld, the upper supplies an overhead 12" rainshower head.

Moving counterclockwise from that wall, the long wall on the right is on an exterior wall, nothing but tile.

The short back wall has a 2-shelf niche, about 36" wide and 30" tall. The lower niche space is 15" high, the shelf itself is 4" thick, the upper niche space is 11" high.

The last wall, the long wall to the left as you enter, has the wall-mounted hand-held. If I recall, the sliding bar is 40" tall.

Tile backer? I prefer cement board on the walls. Wonderboard or Durock. I used Wonderboard on these walls. The ceiling and niche is done in Hardie, as Hardie is less brittle so for me it's easier to cut into narrow strips to trim out the niche, and not as prone to snapping when installing full sheets overhead.

Oh well...

Yup, with translucent, it's all about what's on the back side of the tile. Then...

Start with a flat substrate.

I burn the thinset into the substrate with the flat edge of the trowel, leaving a flat coating about 1/8" to 3/16" thick. You can go thicker, no worries.

I then use the notched side of the trowel and comb out the burned in layer. This removes the excess and leaves a measured amount of thinset on the wall.

I then again use the flat side of the trowel to knock the ridges back down flat.

Now here is where "it depends".

What you don't want to do it place the tile on the thinset and end up with an air bubble. I'll often times "roll" or "rotate" the tile into the thinset. Example, place the bottom edge of the tile into the thinset then "rotate" the tile onto the wall, pressing slightly as you go.

That's very easy to do with smaller tiles. Yours are larger, so that's where Bill's Tip #534 comes into play...back butter the tile. Not too much, just get a thin coat on it. Then place it on the wall.

Clear glass will show what's behind it. If you press it HARD onto the wall and displace the thinset, you may play peek-a-boo with the gray cement backer board in a place or two. It all depends.

White thinset can be tinted to a different shade to change the look of the tile.

The big thing is start small. Practice. Do a small demo board, work on your technique and see how well you go. Once you get it down, remove the tiles off your demo board and you can wash them off, use plenty of water as you don't want to be scrubbing gritty thinset off them, you could scratch them.

Take pictures! I want to see progress pics and the finished job.

Best, Mongo

Okay-- Instead of going down the line answering your questions, I'm just going to outline what needs to be done. Set your mats and then pour your leveling layer, whether that be loose thinset or self leveing compound. LET THAT DRY. Once dry, go back with MODIFIED thinset to install the Ditra. You want modified thisnet to make sure the Ditra adheres to what's beneath it. Unmodeified won't always do that for you. As for the times I've talked about using unmodified thinset under the Ditra, it's mixed with a liquid latex additive instead of water, which makes it MORE modified than most modified thinsets. Once the Ditra is down, I'll then use that same unmodified thinset mixed with water this time, and set the tile.

As for this statement:

For cement board, you want an unmodified thinset.

That's true. In this case, the thinset isn't being used to bond the cement board. it's being used to cushion it and stop vibrations between the layers that would otherwise exist. The screws (or nails) are what holds the cement board to the subfloor-- not the thinset.

NEXT!! :-)