With proper ventilation you should have no problem with moisture running down the walls. There are whisper quiet exhaust fans available, and you can put them on a timer so you don't have to remember to turn them off. When you use your sinks note how high you splash water and put the framed mirror above that level. We have a large framed mirror (3x5') and it is hung on the re-enforced wall with strong picture hangers. I believe I could put a hose to the wall water would run behind it w/o damage...well at least to the mirror itself because it doesn't touch the wall anywhere. You can mount your mirror using a channel on the bottom edge and use mirror clips on the top and the then add your own framing if that works for you. Just take care of the moisture problem in the room first, and then do whatever suits you. -Babka

The others are right, though you need to be careful because a lot of adhesives will attact the silvering (ok, these days it's aluminuming) and you may want to remove it one day - use the special stuff, but most framed mirrors don't use adhesive at all, they're held in place with brads or, preferably, beading. My wife and I obtained some doors that were intended to be glazed or perhaps have a panel in them; ie it's the outer part of the door with an open centre, and we've been talking about making it into some sort of decorative mirror. I suspect buying a made one would be cheaper, but we're thinking of doing something nifty and personal with it. I'd be figuring on beading holding the mirror in, it'll be backless. In the op's situation glue is a good idea, as for the rebate for the edges of the mirror, if you have a friend with a table saw or even a hand saw with a fence, it's very easy to make a rebate/notch that will help hold the mirror in place, even if it's 1/8" - but your gluing thing will probably work but I'd be very careful...you'll probably want to screw the frame to the wall to be safe.

Base cabinets were mentioned once. They would be good bracing! It seems the discussion went towards braces that you buy in a store. To attach base cabinets as bracing one will need angle iron, and a lot of fine tuning work in terms of the cabinet feet and height above the floor. Uh-oh. Sounds impractical now. So, the 90 degree braces at floor level now seem to be the best thing to do. mudworm, on lowes.com I entered two keywords: aluminum tube. I got positive results. Here are some of them. Item #: 215640 Item #: 216100. Go to wherever they have these in the store and you will see steel tube too. Or, web search for steel tube. I just figured that "aluminum tube" would be easier to search for. Buy aluminum tube if there is no steel. Once a metal is made into a tube it is very rigid. In home depot I have also seen steel and aluminum tube. So, tube IS available if you know where to get it. Tube is stronger than thin flat metal. If you add tube on top of the braces you will have both the benefits of what advertguy proposes and the benefits of the 90 degree bracing, and no deleterious secondary impact. advertguy in your latest post "Remove those braces from the bottom" is not clear. Hth

I did this - I used liquid nails for mirrors, bought at Home Depot. Here are before and after pics. I also painted the vanity and the cultured marble countertop, applied a top coat of marine grade polyurethane. This was done 2 years ago as a quick facelift, it still looks the same, has held up well! We are planning to replace the vanity and flooring next year, but it made the bathroom less ugly for the meantime. As far as how-to goes, I had to remove the clips and shoot some of the mirror adhesive down the back, replace the clips overnight to let the adhesive set (now glued to the wall). Then remove all the clips, make sure mirror is really secure and then glue the wood to the mirror. I used crown molding for the top. I chose to do square corners not mitered because the crown at the top was not a miter join (though it was a mitered cut to look right). Before After