The board is not drywall its a type of plasterboard/ wallboard.

The wood you see is furring strips.
If the wood is not rotted, it does not need replacing, water will discolor and stain wood, but that does not mean it is damaged.

If you had acess to a table saw you could easily rip some thicker furring strips thus allowing you to use 1/2 drywall.

PS they make 5/8" drywall but its more money.

A tip for matching the seems, cut the old board along a stud by snapping a chalk line and using a cirular saw with a good carbide blade (more teeth = smoother cut).

Thanks for the response.

I was thinking the same thing, and after I read your message, I began to work on the furring strips. However, while pulling the 2nd furring srip off the wall, one of the thick nails holding it in the brick pulled out a big silver-dollar size chunk of brick with it.

The reason the first piece didn't do this was because while prying them off, the nail heads came out the other end, and the nails are still stuck in the brick :(

How do I remove these nails without damaging the brick wall, and then how do I put in the NEW nails without damaging the brick wall?

If you own a reciprocating saw you can put in a metal blade and slide it behind each furring strip. The rip saw will go thru those nails like butter and you'll never see them once you re-rock the walls. Those nails are doing exactly what they're designed to do which is hold in concrete or brick. I'm afraid your going to keep pulling out chunks if you don't cut the nails from behind

No, I don't :( I have a Dremel, but that would be a pain, hehe.

Hi, Wet sheet rock will swell and stay that way. That may be your problem. Sheetrock is cheap so cut it back to where you are sure its not damaged then go from there. If it is
3/4 thick use 5/8 rock then shim the strips up. Do not remove any furring strips that's a lot of work for nothing.I have found paper shims for sheet rock about 1/8 thick that works well or buy 1/8 cheap panel or hard board cut it with a knife and tack it to the strips then hang the rock on. Remember you don't have make the shim job pretty your going to cover it anyway.
Good Luck Woodbutcher

Hi,
I bet you have a rock lath and plaster wall. It's an old system that came into use to replace wood lath while maintaining the strength, warmth and accoustical properties of three coat plaster. The 3/8" white layer is a thin sheetrock type stuff ("rock lath") made up into 16" x 48" sheets, and applied to the framing (or furring strips in your case) with small-headed lath nails. Then two coats of grey mortar (base coat plaster) was applied and allowed to dry. Finally, a white finish coat of plaster was smoothed out for the finish.
That's what it _was_. It's obviously been damaged beyond repair. To break off the masonry nails, hit them sideways to snap them off flush. or simply drive them in with a three-pound hammer.
You can put up a vapor barrier, new furring strips and drywall.
Casey

Cutting the nails without a recip saw; Poor man's method.

Take a hacksaw and remove the blade. Slide the blade behind the board, above the topmost nail to be removed, and with the teeth facing down toward the nail. Now look at the two clips on the hacksaw that hold the blade. On most saws these can be slipped out, turned 90 degrees, and slipped back in. Do this, and then remount the blade (still behind the board) in the saw. Now you can cut all the nails one after the other.

You can also buy a hacksaw blade holder that holds it from one end only, specifically to make it easy to slide in behind stuff. Cutting anything thick or hard this way is very laborious, but better than nothing if you don't want to go buy a nice recip saw.

It definitely sounds like plaster on the old 24 x 48 rock lath panels. Currently USG makes a 3/4" thick gypsum board panel called Ultracode intended for use in fire walls and a 1" thick panel called Coreboard for shaft walls.

If you need to make 3/4" thick drywall, put two 3/8" thick
drywall together.

I put off buying a Sawzall for a while.. but once I got one, I don't see how I ever did work on my house without it. Get one, it will make your job SO much easier. If you really can't justify a good one, Harbor Freight sells a $20 cheapie that's better than nothing.

Just saw HF selling a recip saw at $15 on sale the other week. Might still be available online.

I rented one for a couple of hours once...pretty cheap.

-Roger