Custom Shower Project Progress & Questions

[siearly]

Make sense?

Yes, it does. I like that approach. Thanks Laz.

[siearly]

Now that the shower is ready for tile, we're going to shift gears and tile the main floor in the bathroom first. I wasn't going to do things in this order but we need to get the main bathroom back together so my wife can pick an accent tile for the shower. We need to see everything in place to get the right colors.

That said, I am working with a plywood sub floor on joists with 16" centers. I already did the deflection calculator and things are a go for tile.

We're installing 16" square natural stone tiles (see one in the picture). I was thinking of using Ditra for the installation. After reading the installation instructions for the Ditra it looks like I use an unmodified thinset between the Ditra and the tile but what do I use between the Ditra and the sub floor?

[Lazarus]

Between the Ditra and the plywood subfloor, use HD's "Versabond." Grey or white, it is slightly modified and sticks really well.... (Be sure to use unmodified on top of the Ditra to set the tiles!)

[siearly]

I have HDs Versibond for attaching the Ditra to the floor but couldn't find any unmodified or unfortified Versibond for attaching the tile to the Ditra. Can I just use any unmodified thinset? I looked at both HD and Lowes and both have a thinset that is unfortified that gives you the option of mixing with water or an add mix. Do I just use that without the add mix?

[Lazarus]

Yeah...use an "Unmodified" morter for thet.....but don't use the very cheep $5 a bag stuff.

[siearly]

Do I use the "add mix" or just water?

[siearly]

I almost burnt myself.

When I did the floor deflection calculations, I thought we were putting in ceramic tile but it is actually natural stone. I have a calculation of 558 (2x10s, 12' span, good condition) which the calculator says is no go for natural stone.

I reread the Ditra installation manual and discovered for natural stone I need to install an underlayment of at least 3/8" over the subfloor. The present subfloor is glued and nailed.

I'm installing 18 x 18 tile. Am I going to have problems if I don't reinforce the floor? There are some walls beneath it which may or may not be supporting it. I ran the calculation assuming they are not structural.

[siearly]

Anyone care to provide input on either of my last two questions?

[Lazarus]

Steve~~ Yes, just use water.

[siearly]

Am I going to have problems if I don't reinforce the floor?

Well, I didn't hear from anyone and so I made a command decision based on what I found in other threads.

I stuck my head into the area under the floor and had a look around. There wasn't a lot I could see but there is a load bearing wall which reduced the span of some of the joists, but not all. I decided to proceed but instead of using 3/8 plywood for the second layer, I used 1/2".

My wife and I installed it today. I followed the Ditra instructions for installation, screws every 6", none in the joists, perimiter screws every 4". We gapped the boards 1/8".

[siearly]

The ditra installation guide tells me what size trowel to use between the Ditra and the sub floor but says to use "an appropriate size for the tile" between the tile and the ditra.

I did the thinset and grout estimator and for my 18" x 18" natural stone tiles, it assumed a 1/4" notched trowel. Is that what I should use?

[siearly]

Anyone? Comments? Suggestions?

I'm leaning towards the following:

1/4 x 1/4 notch to put down modified thinset between the ditra and the plywood.

1/2 x 1/2 notch with back buttering to put down unmodified thinset between the tile and the ditra.

[Lazarus]

Steve~ The 1/4" should be fine for setting the Ditra. For the tile, I'd try a 3/8" and burn a flat coat on the backs. Pull one up and check for coverage. The half inch may be more than you need....

[siearly]

Okay, thanks Laz.

And a special thanks for all your input so far and staying with me.

[siearly]

Did the Ditra today--pretty straight forward. The stuff is easy to work with.

I had hoped to tile today too but after sanding drywall, cleaning the dust, priming all the spackle and new wallboard, wiping down the floor with a damp sponge, letting it dry, vacumming the floor again and then laying the Ditra, laying out the tile and cutting most of it, it was time for a beverage.

My wife wasn't too keen on me wanting to cut every piece of perimeter tile but I really want a balanced layout. She felt a full tile on the two perimeter walls where you would see it would be just as good but I just *had* to have equal size tiles on opposing walls. Otherwise, it would bug me forever. I'm also the type that puts a level on a picture instead of eyeballing it.

Should I lighten up?

Tomorrow my wife an I will do the tile.