It's a basic two gang box. The sides are flat, so this should work - right? The wings that tighten with screws probably won't work because the wall is too thick - they can't slip behind it. I have thought about putting a magnet on a string and going fishing for the metal thing that held the box in previously.

I know you're worried about how the top coat/finish will look but you should consider what's underneath that, first. Plaster is rarely one coat, almost always two, or even better, three. Each applied separately and left to dry before the next is applied. The different coats are made of slightly different materials as they have different purposes, too. But the first thing to think about is the lath. I assume you are talking about wood lath? You said you have bonding stuff, but that's not going to be sufficient to stick the plaster to the lath. It's really intended to stick plaster to plaster, at the edges of the repair, which except in really small repairs isn't enough to secure the plaster to the wall. Plaster works largely because it is mechanically held to the wall when some of the first (deepest-in) coat is squeezed through the openings in the lath and blobs of it form behind it within the wall cavity. When you tore the old plaaster out, you no doubt saw the plaster material behind the lath, that wasan't sloppy work, it was an essential part of the plaster. Through a chemical curing process as the plaster dries the material on the room side of the lath and the blobs behind are permanently bonded together around and through the lath. Subsequent layers of the plaster are bonded to the deepest layer (and to each other when there are multiple coats) by a reactivation of the chemical reaction as they are applied and then dry. But the strength of the wall is based completely on the integrity of the first coat's attachment to what's behind it. The blobs are called "keys" and in a mechanical way they "lock" the first coat plaster tight to the lath. The strength of this layer comes because a chemical reaction occurs when the plaster dries (cures) slowly enough to become rock-hard and tightly stuck to the rough surface of the lath. Originally the wood lath (like all new wood) had enough intrinsic moisture content that it did not suck the moisture out of the drying plaster prematurely which would interfere with the vital curing process,thereby weakening the plaster. However when you are dealing with old lath (that was original to the wall), which is now almost tinder dry, you can have a problem. One solution is to try and re-wet the lath by spraying it to the run-off point repeatedly over several days just before starting the repair. You can also strengthen the repaired-section's adhesion to the lath and to the wall by attaching over the wood lath a section of expanded metal lath. Cut it to roughly fit the space and screw it to the wall studs. (Don't tighten the screws down so much that the metal lath is distorted and pulled down into the spaces between the lath strips. You want it to be a flat, secure plane lying just on top of the lath.) Do not use nails which can cause additional plaster pieces nearby to crack and come off. Very small repairs (6-8" holes) can get by with just attaching (withwires, or careful stapling) the expanded metal lath to the wooden lath itself, but anything larger needs the metal lath attached to studs. Your first coat of plaster is a rough coat and its pupose is to get good adhesion of the plaster to the wall so it gets troweled onto (and through) the lath pretty firmly. It should remain completely below the surface of the finished wall and there's no need to make it more than nominally flat. It is usually a much coarser mix and slitght roughness on its surface helps subsequent layers stick to it. Only scrape off big lumps which would interfere when the next layers are smoothed on. The first layer is allowed to dry and another one or two coats are added on top to fill the remaining space and bring the repair up to the same plane as the wall. Each will be slightly different in composition; the final one being more fine, and/or in your case more textured. As recommended above I would definitely try as many trials of your finished texturing as necessary before doing your wall. You needn't used multiple coats while you are practising the top coat texturing. Just try the finish samples on scraps of sheet rock over and over until you've got the technique for the final coat down to a satisfactory match. Top coat plaster sets up quite quickly and you want to be able to apply it, work the texture and be done before that happens. Before starting this job I recommend doing some more research on working with plaster. There are instructions in books on old house repair and from time to time in magazines that deal with old houses. You should also know that depending on the age of your house modern plaster available for repairs and orginal plaster are not the same thing. However for a small repair I think I would use modern materials rather than trying to source and work with older formulas. HTH L.

You say that the drywall is breaking down. It normally won't break down unless it has gotten damp or wet. I think before you cover anything up you should determine if there is a problem. If there is correct if first. The plaster loosening up is fairly common. It could be for a number of reason, but I think you should still be sure that there isn't moisture problem there too. As far as covering the existing walls without removing the old stuff.....I have personlly covered I would guess 40 or 50 rooms and ceilings over the years without tearing out the old stuff. Is there insulation in the walls and will you ever need it there? Celulose can be blown in from the inside and, of course, that would be done first. If the walls aren't in too bad of shape I go over everything with 3/8" drywall and use lots of screws. Where you are going over plaster and lathe you will sometimes hit studs, but often just the lathe. The screws into the lathe will hold as long as you use lots of screws. Over the drywall you will have to locate and hit the studs with screws. Also on going over the drywall, you will have to end the pieces over a stud just as if you were applying it to bare studded walls. If you end it between studs there will be nothing to hold the edges and the job will be ruined. When I go over existing walls I make sure that any wiring that might be needed is done first. If necessary I make holes to run wire. If there are any real uneven spots on the wall I shim out the low spots with scrap pieces of 1/4" or 1/8" luan or paneling. I don't remove the door and window casings or the baseboards. I run the drywall right up against the casing and fill in any gaps with mud when I am taping. Now a lot of remodelers won't agree with going ovre the existing, but I've never had a problem as long as I've used plenty of screws that are long enough to penetrate the drywall or the plaster. If the walls or ceilings are terribly uneven you might have to use 1/2", but I've always used 3/8".

From the interior you cut-out the damaged lath and treat the entire area on the inside and as much as you can reach along the edges on the outside using something like Bondo Wood restorer or Rust-Oleum Coppercoat wood preservative. After it dries, use 2 pressure treated 2x4's and nail 1/2" pressure treated plywood to the face of it, make it as wide as the wall cavity between the stud, put inside and nail it and insulate and close it up. Something like this.