1) is this a good order of installation?
Yes

2) how much reveal is best for the counter/sill?
It depends. Structurally, if the bottom front edge of the niche is dead flat...no bow in it...no wobbles in it...you can go with a smaller reveal. For example, if your wall waivered in and out 1/8" and you put a 1/4" overhang, the overhang would vary in and out across the front of the niche, and your eye would pick up on it. If you went with a 3/4" overhang, that 1/8" of wobble wouldn't be noticed.

But something tells me your wall is dead flat. 8 )

Capillary action: If you think the niche will see a bit of water spray, you could cut a drip groove on the bottom of the shelf. It doesn't have to be significant, even a 1/8" deep groove will do. What the groove does is it stops water from running down the face of the shelf edge and then being drawn back to the shower wall below the niche via capillary action. Instead, the drip groove breaks the capillary action and water will simply drip right off the front lip of the shelf and on to the shower floor. It's not a requirement by any means, and if you go with a smaller overhang, there's no room to do it. I just thought I'd toss it out as a consideration.

When I do overhangs for niche shelves, I'll usually make a roughly 1/2" to 3/4" overhang. Material thickness can be a player. If your shelf material is too long you can also cut return ears on the ends. The size of the shower can be a consideration too. You don't want to catch an elbow on an overhang.

While the photo below shows a drip edge groove cut into the bottom of a stone door threshold, the idea is the same. Your groove, should you decide to cut one, does not have to be this deep. You don't have to carry it all the way to the edges either, you can stop it 1/2" to 1" from the ends of the shelf. Again, it's optional.

If you go with a smaller overhang, don't worry about the groove.

3) would there be a problem if I had no reveal of the sill, or just a very tiny reveal (such as 1/8")
No. As long as the bottom edge of the niche is flat/straight.

4) If I had more of a reveal what is reasonable? Is something like .5 or .75" a sensible amount or too much?
It's sensible. If you have a thin shelf, say 1/2" thick, then you'd want a smaller reveal. If your shelf was made from 2" thick material, you could go larger. I do prefer the overhang to be less than the material is thick. ie, with a 3/4" thick shelf, then I prefer a 1/2", or maybe a 5/8" max overhang. And you can always go less. With 2" thick material, you could overhang 1" to 1-1/4".

5) Does my shower curb product sound like a good way to go with the niche shelf?
Sure. I've used stone curb/thresholds/saddles at times for shelving.

Aside: Travertine is pretty easy to edge detail with a grinder, even with regular grit sanding pads. Start at 60 grit to rough material away, then work through to 600 grit for a nice smooth surface.

OH GOODIE, thanks Mongo! The sill I have considered is .75" thick so I will consider a max of .5" over hang, using the guideline you mentioned above, I like it. I hope the carpenter did a "dead flat" wall. I haven't put an edge to it yet. I think I better go do that to see what I get.

I don't want much protrusion into the shower space so we don't bump the shelf with elbows. Since the shelf is so long I am not concerned about getting extra counter space with a bowed edge.

Questions:
1) if I put dog ears on the sill, do I first do the above order of installation, then cut and install the main wall tile around the ears? This sounds like the way to go to me.

2) Or, do I place the the tile on the wall then put the shelf in place over the tile. This would be wacky though, as I need to place the flat wall tile on top of the niche tiles to hide the cut edge of the side niche tiles and to do this the sill will need to be placed first.

Here are my detail drawings of installation as in question 1.
Detail #1:

edited to relink drawings

This post was edited by enduring on Wed, Dec 4, 13 at 20:37

Because of the size and location of the niche, #1 certainly sounds easier. And it'll give you a stronger dog ear, as about 1/4" of it will be buried within the tile.

Example, before tiling the wall, your shelf and dog ears will protrude about 3/4" out from the cement board. Then when the wall tile goes on the cement board the 3/4" protrusion will now only be 1/2" exposed.

With a 1/2" protrusion, don't bother with the drip groove.

If the bottom edge of the niche is a bit wobbly, you can compensate for that uneveness when you tile.

Thanks Mongo. Also thanks for the info on the grinder. I will try this out on a scrap. I took a 4' length of laminate flooring and checked for flat on my wall. The nice straight machined edge is perfect and handy. Near the center there is a slight concave bend to the wall that is about 1/16" or less recessed from the ends. I think that will be negligible.

As I re-read your post about dog ears, I guess I drew my details wrong. I had been thinking of just setting the stone in the niche and using the tile depth of the niche sides to determine my "ear" length. But in my second drawing it all of a sudden looks longer, like I actually notched the stone. I will have to do some scale drawings to determine exactly what I will be doing. Short ear or longer ear. The longer, notched ear might look better if there is a reveal. The shorter ear might look best if I make the sill flush with the tile.

I recently read in one of your posts that you tend to not respond to design questions. So I understand if you don't give your opinion on this detail.

I don't at all mind opining on your question. When I sometimes don't reply to a design question, it's because design preferences are really in the eye of the beholder. I mostly shy away from design things like color choices, or does "this vanity go with that tub" type of stuff.

As far as design with regards to room or fixture layouts, or how to scale something to something else, I'll toss out ideas if I have one.

My original though of the dogeared shelf would have been to notch the shelf so the dogear extended beyond the edges of the niche. Not just the niche sidewall tile, but beyond the niche sidewall cement board too. But that would have been if you were going with more overhang.

Since your shelf will only have a 1/2" overhang beyond the wall tile, having a 1/4" dogear would look fine.

That means that yes, you could have a rectangular shelf with no notched dogear. Just a plain rectangle. Set that rectangle of stone in the untiled niche. Then when you tile the niche sidewalls, the tile thickness will give you a 1/4" dogear.

Now if you wanna know what color curtains to hang and what material to make them out of? That's out of my league. lol

Great, thanks. I think I'm set with the niche>

Curtains? I was thinking of a cowboys and bucking broncos motif, with a light blue green background. I don't want a south western theme though; something more prairie-ish. What do you think :)

A prarie-themed design?

Why how about a nice big Laura Ingalls Wilder fathead stuck on your bathroom wall? Or Michael Landon and Melissa Gilbert?

Here's one of Dustin Pedroia to get you in the mood:

I think I was mistaken. I am good at design!

ROTFL! You are good!

But:

(edited to say that I do root for the Red Socks when appropriate :)

This post was edited by enduring on Thu, Dec 5, 13 at 15:54