You need to figure out how water is getting into the studs. Once that problem is solved plain wood wil be fine. You should sister on new wood about 12 inches ablve the rot, fasten with screws (nailing can cause plaster damage), and then remove as much of the rotted wood as you can. If the wall is weight bearing you should sister the other side after removing the rot. Matal brackets (Simpson Strong tie) to attach the ssters to the bottom plate work well. You need to chek the bottom plate for damage also. They can be more work to replace depending on how extensive the damage is, but still not really hard. I am just finishing up a basment repair. The bulder back around 1972 used non-PT wood for the bottom plate of a simple curtain wall in a basement. The plate has serious rot prolems. After checking the attachment to the joist above, I sawed through the nail attaching every stud to the plate, then hammered tha plate out (it was rotten enough to break up pretty easily). A new PT plate (below grade maonry contact), brackets, some stainless fastners for the bracket to the PT and regular galvanized TECO nails for the bracket to stud and everythig is back in shape.

First off, I say it's a wonderful idea - I did the same thing between a kitchen and dining room and have been very pleased - adds interest and practical benefits to both rooms. Main thing I question is your width calculations. You initially said 2', but they you said between the studs, which is more likely about 14". I don't think 14" is wide enough for a window, so you'll probably have to "header up" one stud, especially if it's a load-bearing wall. It's still doable, and in my opinion, worthwhile, but there will be a little more framing involved and you may have to make the opening bigger to give yourself room to work. As far as cutting in goes, I used a reciprocating saw held at a very hard angle to cut through the plaster first, then angled in to cut the (wood) lath. If you're cutting right next to a stud, cracking adjacent plaster should be less of a problem. Psteenhoek's idea of using a circular saw with two blades sounds theoretically better, but the problem with plaster and high speed blades is dust, and lots of it. I prefer easing in a recip saw blade to cut the plaster, clean out the loose plaster, then get a new blade to cut the wood lath. It takes a bit of a touch with the recip saw, but is much less dusty than a circular saw cut (though still dusty enough!)

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.

It sounds like you have what you need, and that you just need some practice. Any corded drill (or cordless) can handle this job. It sounds like you have standard, inexpensive bits which are usually high speed steel (HSS), and those are fine, too. You may want to get some better quality bits (like titanium coated) in the future. Unless your walls are actually concrete, you have no need of specialty tools, like a hammer drill or masonry bits. Impact drivers are wonderful specialty tools for driving fasteners into tough materials, but it would be the wrong tool to use on this project. (It would be nice to have a cordless drill-driver if you are driving screws, but you don't absolutely need that, and you need to master the use of a regular drill first.) Plaster drilling dulls bits faster than using them in wood, so you might want to have some extra bits on hand. And even though I have been using tools for over 50 years, I, too, occasionally break small diameter bits, so I keep cheap spares around. While I tend to buy high quality power tools, when it comes to disposables, like bits, I look for bargains since I do a lot of drilling; for your drilling needs, you might want to look at a place like Harbor Freight tools: Drill bits You can get decent bits there for cheap, including things like a set of half a dozen 1/16" or 3/32" or 1/8" bits for a couple of bucks. They have stores in many areas of the country and you can buy online. Too many homeowners have one set of bits that get dull early on and never get replaced, so I suggest you pick up some extras and toss them out when they quit performing well. Good luck, and tell me what happens when you try this again. Do you think it would help your skills development if you practice drilling into a scrap of wood first, just to get the hang of handling your new tool? I also assume that you have a standard variable speed drill, and it would be better to use it at a slower speed when going in to plaster. And did you confirm that the forward-reverse switch was in the correct position? :-)