you could use a plain slab like panel for the front, and tile it. You will need some trim pieces along all four edges to finish it, unless you make it the exact same size as the tile.

Not sure about making it waterproof, I suppose for the door you could add some weatherstripping and make that fit into a groove on the mating surface. for the wall you could add a layer of membrane between the backer, and the cabinet

I saw this post by mongoct. He used a cabinet as a frame for the pony wall - will not work for us since we will have a continuous tub frame... Beautiful solution though.

Thanks for your advices Sloyd! I was thinking about framing the door/front panel with Schluter tile trim pieces (Quadec) to make it look finished. I will use this trim in my design anyway.
I plan to use Kerdi as a membrane.

I still can't figure out how to frame the drawer and how to install the hardware for the pull-out inside the frame.

Also, we did a lot of tile projects, but we never used Kerdi before. Should I make the frame out of plywood and attach cement board+Kerdi on top of it? Or just cement board attached to 2x4 plus Kerdi? Should we install some kind of floor piece for this drawer? It looks like these pull-outs are mounted on the bottom of the cabinets mostly.

We built a pony wall into two bathroom's tubs feet like this but just made them about the same height as the tub wall and inset a bookshelf in each. I really like the extra space. We're kinda readers so that space goes to *very* good use. Plus, there's a reading holder thingymabob beside each toilet. Plus, um, they're all overflowing anyway. Books expand to fill the room available (+ one), right? Same as stuff and closets....

Only thing I'd do differently is consider raising the height of that wall as is in your picture for more shelf space! Plus, don't forget to *paint the stupid shelves first*. Geesh. One of ours is now tiled but unpainted: what was I thinking (stupid).

I like the side access that shelves give to the toilet-ee, but if you're just looking for more storage space the rev-a-shelf route makes sense. We have a houseful of people who like to snuggle into that space there for a good long while though! Very handy and gemutlich with the shelf.... :)

BTW, we tiled up and all around the pony wall, just not in the shelves. Ends are bullnosed. I'll try to find a picture if anyone's interested.

You will have to build the wall like a cabinet, so the frame will fit inside the wall. Here is a good link, on how this guy made the sliding spice rack.

Here is a link that might be useful: sliding spice rack

aliris19,
I would love to see the pictures of you bathroom book shelves, please post them!

Sloyd,
thanks for the link. I did not come across this one, so it is very interesting!

Waterproof membranes like RedGard and HydroBan can be applied over exterior plywood and cement board.

Since I'm not a fan of using exterior plywood to make a cabinet carcass, I'd recommend making the cabinet carcass out of regular 3/4" plywood. Birch, etc. Then cover the side with 1/4" cement board, then HB or RG or Kerdi the cement board, then tile on the membrane.

You could frame the cabinet with 2x4s and skin the frame with 1/2" cement board. But using 3/4" ply and 1/4" cement board will give you thinner cabinet walls, more internal storage, and a better quality cabinet.

Traditionally installed drawer slides typically require 1/2" clearance between the side of the cabinet and the side of the drawer. So if your pony cabinet has an internal width of 10", make your drawer or pull-out unit 9" wide.

Though you can use any brand, I do prefer heavy duty KV slides. They have 100#, 150#, 200# slides etc, that can carry pretty much any load you throw at them. I recommend you use full-extension slides.

Thank you for such a detailed response Mongo!

I guess it will be even more clear when we will start the project.

Few more questions for now:
1. What would be the best way to treat the inner side of the plywood that will form the cabinet - polyurethane? Paint? Some epoxy stuff?
2. Do you think that the same 'sandwich' of 3/4" ply and 1/4" cement board + tile would work for the front panel of the pull-out? Is framing this panel with Schluter Quadec trim a good idea?
I thought it will look better than leaving a gap around the panel. I know that even panels for recessed openings for whirlpool motors are recommended to caulk so they are less noticeable.

Alina - we didn't do a careful job at all. I just asked a kinda slap-dash guy to throw together a bookshelf made of 3/4" pine I think. maybe even 5/8". I'm not recommending this, certainly not over what am actual cabinet maker constructs. Only, this is just not something I fussed about at all. Course, this happened early on in the experience when I knew -8b. I know more now and might be more careful about all this.

And I'll show pictures because I want folks to see but ... it doesn't look very good in pictures, neither of my bathrooms does! The colors are wrong and you just can't get a sense of the feel of the room *at all*. One of my bathrooms I posted because of a problem with the vanity top and I got a little sub-enthusiasm because I know my "Style" is no way-no how GW's! I wish I *could* convey with a photo what the room actually looks like because I do really like both and think you-all would too if only I could depict it fairly! As well, over in kitchens I once set off a mild scandal-storm by showing a picture of another bathroom that contained wet footprints in it, and of my kitchen once all overflowing with a typical day's worth of chaos from a really, really busy household. I am just not living the GW life here.

So - all those mea culpas aside, please understand that I do recognize my life style is perhaps a little shocking to some on this forum. As they say on the net, no one knows that you're a dog. All I can say is -- it works in person!

So here's a closeup of the shelves that are smaller because of the room's configuration in one of the bathrooms. This is unfinished and unused, but we're getting closer! Darn it, I should have removed the offending personal items and put the toilet seat down for this photo, but it's now beyond a waking person's reach, if you follow:

And here's an overview of the space if it helps. Please know this wall is no way so blue in reality. I'm thinking the glossiness might have caused the flash to bounce and change the color a lot? It is a little bit blue but in there it looks grey-blue:

The serpentine in the niches was supposed to go on the floor, but when I went to order it, the warehouse said a hotel chain in Arizona had just bought hundreds of thousands of sqft of the stuff and it was now all gone. I was really disappointed! But I got to keep the sample and that's where it ended up. The replacement floor is more muted but it's OK, particularly given the top I was therefore able to "afford" (in the wild-stone expense account that is).

For your interest, here's a shot of that wild-stone:

And here's the shelf in the other bathroom. These shelves are bigger but obviously not being used to great affect at the moment. If you cared about use, appearance, efficiency, etc, you should just build the pony wall to a height that will give your bookshelves the height they want or you need. I didn't do that, just sort of fit them into a random height built to contain the tub. That was silly I suppose, but designing this was not on my mind at all at the time:

Here's a shot of that space for reference:

And because I posted about this problem sink of mine earlier and showed some shots of the bathroom at the time, I'll show the other wall and the new top to that problem vanity. The old problem sink is, sadly, gone (broken) and everything works *way* better. BTW, at the time someone (well-meaningly) criticized the diagonal tiling backsplash as not representing a angularity anywhere else in the room. That's not actually true, but you cannot really make it out in the photo; the entire white tiling behind the tub is on an angle and the spots are set in, therefore, at their junctions, also as an angle, a sort of "diamond on the side", as it were. What can I say -- I think it works in person. If you stare hard you can just make out the white-on-white diamond pattern of the tub. So that has white grout, the sink area blue to pick up the transluscent tiles. That luminescence also doesn't photograph well:

And finally, because there was a discussion of "boob lights" elsewhere which I personally found just hilarious, I show here a shot of my decidedly not-boob lights. I can't get what they look like when turned on, they emit a slightly red and blue-green streaky white color -- it's pretty wild. Unanticipated, but really looks very cool. I picked them in large part because they worked to the *left* of the electrical box. Those got put in in the wrong place and I just didn't feel like moving them. Decorating-by-sloth. :)

OK, please understand this all works better in person than in photos. I know it's a real faux pas around here to show traces of life-with-teens but I just don't have the energy to clean up behind them or for a photograph. Mea culpa!!!!

"1. What would be the best way to treat the inner side of the plywood that will form the cabinet - polyurethane? Paint? Some epoxy stuff?"

You can prime and paint if you want to hide/color the wood or use poly if you want to leave the natural wood grain showing. You don't need any waterproofing in there.

"2. Do you think that the same 'sandwich' of 3/4" ply and 1/4" cement board + tile would work for the front panel of the pull-out? Is framing this panel with Schluter Quadec trim a good idea?"

You only need waterproofing on the tub and shower sides, so on the front of the cabinet and on the face of the pullout you could actually tile right on the plywood with mastic as your adhesive. Mastic is fine for an application like this.

At first I'd tile the cabinet sides but not the pullout front. Once the pullout is installed on the slides and set into the cabinet, then I'd tile the front of the pullout. That way the tile on the face of the pullout will align with the tile that wraps around the sides of the cabinet.

You could use a Schluter edge or termination strip if that's the look you're going for. If the tile is a through-color tile where the face of the tile is the same color as the exposed cut edge, you could leave the cut edges exposed. But if your tile of choice has, for example, a light-colored glaze over a different colored bisque/ceramic body and the cut edges would look awkward if they were left exposed, then a termination strip might be the thing to use.

Hoping to construct this type pony-wall at the end of our shower-surround, and include the sliding drawer inside the pony wall. Does anyone have experience in doing something of this sort?