Tiling a shower enclosure - questions re: hardiebacker & wall prep

DyerWolf

Hey all. I'm preparing to tile a bath / shower enclosure for the first time. (No previous experience with tile - except for a tile class) I'd appreciate any advice.

Unfortunately, I've been told different things from different sources about the proper wall prep; now I'm confused. When I took out the old tub and vinyl shower enclosure it left the studs and fiberglas insulation exposed. That's where we start: new tub inserted & exposed studs.

Here's the list (please critique):

• I should just screw the hardibacker to the studs with corrosion resistant screws, tape and seal the joints, then apply the thinset & tile.
• I should install a 6 mil plastic sheet vapor barrier over the studs, then the hardibacker, tape & seal, apply thinset, and tile.
• I should install a 6 mil plastic sheet vapor varrier over the studs, then greenboard, then hardibacker, tape & seal, apply thinset, and tile.

Which is right?

Or are they all wrong?

TIA

Scott

ACobra289

When I did my shower, I used redguard over the hardi. Whether you use plastic under the hardi or a product like redguard over it, you NEED to have a vapor barrier.

No need to use greenboard at all.

Good luck with your project.

Termite

Hang your 1/2" backerboard straight to the wall with backerboard screws. Tape and "mud" the joints and corners with mesh backerboard tape and thinset mixed FROM A BAG...Don't use the pre-mixed stuff.

As for waterproofing, I wouldn't suggest using plastic behind the backerboard. Using a topical waterproofer will keep water from ever penetrating the backer. RegGuard is a very common and popular product for this. You simply paint it on. Works great.

Use modified thinset to hang your tiles. Never never never use mastic in a wet area.

angus242

My recommendations for this are:

Insulate with non-faced fiberglass bats.
Use 1/2" DensShield for the walls. It's lighter than most other tile backers and therefore, easier to install.
Hang using alkali-resistant screws.
Tape the seams with an alkali-resistant tape.
Use non-modified thinset over the tape.
Waterproof with Kerdi. Install using non-modified thinset.
Address gap between tub flange and wall with Kerdi-Fix.
Tile with non-modified thinset.
Grout tile. Caulk corners, bottom & top row (if you tile to ceiling)
Seal grout.
Enjoy your tub for a long, long time!

If you don't use Kerdi, at least use RedGard, although it's not my favorite.

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Angus

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gma2rjc

How far down on the flange do you bring the bottom of the lowest tile? Sanded or non-sanded grout?

DyerWolf

Unsanded grout.

I'll probably bring the lowest tile down to 1/4" from the edge of the tub and run a bead of sealant.

angus242

1/8" gap. Use silicone between first row of tile and tub deck.

Sanded for > 1/8" grout line. Unsanded for < 1/8". 1/8" can be either. Any glass or polished stone tiles should be 1/8" or less grout line and use unsanded so as not to scratch the tiles.

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Angus

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DyerWolf

Thanks. Yeah, the pattern I'm using incorporates some glass tile mosaic pieces - which is why we went with the unsanded. I'm already using 1/8 spacers - but had read somewhere that a 1/4 gap was needed between a vinyl tub insert & the tile to allow for expansion / shifting.

I like the idea of doing a 1/8 gap better because it will be a more uniform & seamless look.

angus242

To be clear, the TCNA does require a 1/4" gap. I have found that a heavy 1/8" (maybe close to 3/16") will suffice.
When you caulk, you can fill the tub with water and stand inside of it. This will expose the largest gap that occurs. From there, the gap should only contract.

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Angus

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DyerWolf

Oh - another question:

I initially planned to use 13" ceramic floor tiles for the shower enclosure which matched up nicely to the glass tile mosaic (13 inch sheets). Unfortunately at the last second, my wife decided she wanted a different look for the adjacent tile; and I couldn't find any 13" tiles with the look she wanted. However, I did find 16 inch tiles she likes - which I planned to cut down to 13 inches to marry up to the glass mosaics.

Is there any problem doing this? I figured I could use the rub stone to clean up any sharp edges for the inner tiles & use the pre-finished edges along the outside edges of the whole enclosure.

The other option would be to cut 3 inch sections of the glass mosaic pieces to match the size of the 16 inch tiles. Either way, I'm looking at a lot of cutting; but what's most important is the finished look of the job.

Any suggestions?

Great idea! Thanks!

angus242

Well, the decision is yours but I'd be concerned with the cut edges. You should try to keep cuts to the perimeter (corners, ceiling, etc). It's not a safe bet to assume you can mimic the factory edge profile with a rubbing stone. If you don't mind the difference, it can be done. However, will you be OK with the results once completed? That's a bad time to become unhappy about it.
Designing a shower tile layout is not easy. The battle between feasible patters and tile dimensions is a tough one. My suggestion? Decide what's more important to you (ie, the wife!), the pattern or the tile. Now, base the design off which one wins. You may have to change the pattern to fit the tile or buy tile that fits your pattern.

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Angus

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