1. Are all the Durock seams inside the niche taped & mudded like the rest of the alcove? How about the 4 outside edges (the perimeter)?

Being that it's all supposed to be waterproofed, and most waterproofing systems also double as crack suppression membranes, it's not really necessary, so long as the joints get filled in order to keep a continuous membrane, but it wouldn't hurt to tape them, either.

2. If the bottom should slant a bit for drainage, do you slant the 2 x 4 or build up the back of the tile with thinset?

Build up the back of the tile. It only has to be about 1/16" higher than the front.

3. I saw a step-by-step set of photos for installing a premade niche. Is there one for building from scratch?

Not really. Pretty much what you want to do is figure out where yout tile coursing is going to land, and then set your framing, taking the thickness of the Durock and tile into account (also figuring about 1/16" for thinset and roll-on waterproofing. If you're going to use Kerdi, figure about 1/8" for thinset and WP). You then frame the niche (giving yourself a little play that can always be built out with thinset later), Durock it, waterproof it, and tile it.

Piece of cake! :-)

Bill- One more question:

I want to put a couple of glass shelves in the niche. How are they fastened to the sides? TIA.

>it wouldn't hurt to tape them, either

Yes, it will, if you don't allow for that thickness in your calculations and are making your niches fall within your pattern! (I just had to attack mine with a box cutter and re-Redgaurd--too much height build up.)

As for the sources, check this out:

http://www.technologylk.com/__1591/glass-shelf-supportsamp44-clamps-and-brackets.html

Just lock your shelves in when you tile them. It sets on one tile, and the top tile sets on the shelf.

Yes, it will, if you don't allow for that thickness in your calculations and are making your niches fall within your pattern!

That was my reason for this statement:

Pretty much what you want to do is figure out where yout tile coursing is going to land, and then set your framing, taking the thickness of the Durock and tile into account (also figuring about 1/16" for thinset and roll-on waterproofing. If you're going to use Kerdi, figure about 1/8" for thinset and WP). You then frame the niche (giving yourself a little play that can always be built out with thinset later)

I want to put a couple of glass shelves in the niche. How are they fastened to the sides?

What Laz said. Set your back and two side tiles up to the point where the shelf is going to go, and then set your shelf, putting just a bit of thinset on the side and back edges, and then set the shelf on top of the edges of the niche tiles, maybe using a small wedge or tooth pick under the back edge to give the shelf a slight pitch outward.

Bill- A very minor follow-up question about the shelf, no big deal, I feel a little silly for asking, but:

I understand what you and Laz are saying about simply laying the shelf on top of the tiles inside the niche. This is easy to see in your second photo. But what if I don't want to position the shelves right at the ends of the tiles? I suppose I could cut the tiles, of course, but not sure how that would look.

Would a good quality silicone caulk be sufficient to hold a glass shelf to the tile???????????? TIA.

I suppose I could cut the tiles, of course, but not sure how that would look.

It should look okay, so long as you cut all three sides the same size.

Would a good quality silicone caulk be sufficient to hold a glass shelf to the tile????????????

Not sure I understand you-- are you talking about siliconing the shelf to the FACE of the tile? if so, then no, I wouldn't trust it. If you're talking about installing it the same way as I've installed the tile shelves, then thinset would still be the thing to use-- you're only trying to lock it in place.

>(giving yourself a little play that can always be built out with thinset later)

Sorry--I wasn't arguing. I was just reinforcing that, and a non-fabulous non-pro. :-) More play is better than less. If you're going to do something that will cause build up, then you want more play!

I've seen glass niches installed the way you're describing, Bill, but I'm a trifle wary of them. What if one breaks? There's no way to install a replacement in the same way. (And if you think no one would possibly break one, you haven't met my son... :-P) The examples you show are gorgeous, and they're exactly what I'd go for if I weren't doing glass myself, but with glass and the replacement problem, I'd stick with clips. Just in case.

If you're worried about the probability of them being broken, maybe it might be a good idea to go with something that might be a bit tougher to break-- like corian?

Not if you want the look of glass. :-)

Guezeman over on John Bridge's forums used one of the glass grippers I linked to above, and they looked great--IF that's the style you want. (I hunted them down after I saw them on one of his installs....)

Also, if $$ is an issue, glass is cheaper, even custom-cut, as long as you don't ant a curved edge.

Jim's find is a good one, but that still doesn't address the problem of breaking the shelf, which would beed to be tempered, meaning if it breaks while you're in the shower, it's going to be in a million tiny pieces. From the sound of your post above, this is an eventuality, not a possibility, and I'd be more concerned with someone cutting their feet to ribbons than I would the ease of shelf replacement. That's why I suggested the stronger material.