how do you fix plaster board to a wall which has a hole 48 inches by18 inches?

Answer 1

I'm going to assume you mean a sheetrock wall, not actual lath and plaster -- that's a WHOLE different process from what I'm about to describe.

Depending on the orientation of the hole, you should have at least part of one stud exposed. If the 48" dimension is horizontal, then you shoul have part of at least 3 studs exposed. For best results you need at least two studs for mounting your patch, so if you can't see two studs, open the hole enough to expose enough of at least two studs to get a screw into. (It helps if the hole is fairly square too.)

Cut your patch to the size of the final opening minus about 1/16" all around to allow for irregularities in the edges. Score the surface of the sheetrock with a utility knife until you penetrate to the gypsum core, then "snap" it by aligning the score line with the edge of a hard surface and breaking the drywall over the edge. Then finish the cut through the backing paper with your utility knife.

The next step is optional, but will give you a smoother seam. Measure the width of your joint tape and divide by two. Assuming 2" wide tape, measure a line 1" from the edges of both the patch and the hole all the way around. Then using a straight edge and your utility knife, carefully score each line down to the gypsum core. When the scoring is done, peel away the outer layer of the sheetrock to expose the core material. This will provide you a recess for your joint tape and avoid having the mating seam "proud" of the surrounding wall.

Position your patch and attach it securely to the studs with drywall screws. One screw per 16" of stud is ample, but you should probably have a screw within 2" of the patch edge to make sure it stays flat. You'll want to drive the screws so that the heads are slightly below the surface (they'll countersink themselves in the soft drywall) so you might want to use an electric screwdriver or drill to do the driving. If the hole and/or patch isn't perfectly quare, you may have to shave the mating edge(s) with your utility knife to fit the patch.

I recommend using a wide bladed putty knife for applying joint compound. You can get plastic ones in the hardware store for about a buck. I usually use one that's twice the width of the joint tape. Apply a layer of joint compound to the seam. If you used the recess technique above, you want to just fill the recess.

Then apply the joint tape to the wet joint compound and smooth it with your putty knife or a "taping knife" if you have one available. They're essentially the same tool, taping knives are usually wider, and the blade is squarer. But since you're presumably only working on a flat surface and not in a corner, the putty knife will do the job just ifne. Make sure not to leave any wrinkles in the joint tape. Any little wrinkle is going to show or at the very least create a hole with a "fuzzy" edge in the tape when you sand. Press the tape firmly and smoothly into the compound until it is flush or slightly below the surrounding surface. A final word on joint tape: There are a number of types ranging from ordinary paper tape to plastic mesh. I've tried several, and never noticed that any gave better results than the plain paper kind. So I suggest putting your money into something else rather than buying fancy joint tape.

Cover the joint with more joint compound, extending about an inch past the edge of the tape on both sides. You want to get this layer a smooth as possible while it's still wet so you don't have to sand as much later. Wetting the blade of your spreader (putty or taping knife) can help with this. Just dip the blade in water before working the "mud". Use about a 10-15 degree angle on the blade to fill and a 30-45 degree angle to level.

Allow the joint compound to dry completely. How long this takes, depends on the thickness you've applied and the temperature, humidity, etc of the room you're in. An electric fan may help speed the process up some.

When the compound is dry, use a sanding block or "drywall float" (available in any hardware store from a couple of dollars up to $15 or so) and drywall screen to sand the compound down smooth. Drywall screen is a fiberglass mesh that does a much better job on joint compound than ordinary sandpaper. Sandpaper "clogs" very quickly when sanding joint compound and requires much more effort to get a smooth result. So unless you're really REALLY broke, spend the few dollars for the screen.

Sight across the patch occasionally to make sure you're getting it flush with the mating surfaces. Low spots can be filled with more joint compound if necessary.

If you ... no, make that WHEN you find those tiny voids in the joint compound after you've sanded, you can spot fill those with spackling paste. Usually you can get that smooth enough with a putty knife that you don't need to do additional sanding. simply press the paste into the void firmly with a flexible blade.

If necessary, allow everything time to dry/harden/cure before painting. Use a "new construction primer" on any unpainted surfaces to seal the new sheetrock and seam (Otherwise your paint is going to soak into the patch and leave a highly visible mismatched section when you paint. Depending on the primer, you may need more than one coat. (I've used several, but my best experience has been with Enterprise New Construction Primer from Lowe's. Glidden PVA also works well.)

Then paint everything and you're done. If you've done your job well, you'll never know there used to be a gaping hole in the wall.

Answer 2

Put some batons of wood behind it attached to the wall, screw in the platerboard piece then use normal plaster to go around the edges for a nice finish.

Answer 3

there is an umbrella type device that you can buy and insert in the wall and bull it like an umbrella and then you cut of the rod that you pulled and that gives you a hard back to plaster and then use touch-up

Answer 4

you cut the rest of the board out until it lands halfway on a stud,then screw on a new sheet.tape the seams,cover them with joint compound,sand them,cover again if needed,apply primer,or plaster,paint...presto...no more hole.

Answer 5

get some 3x2 cut them 30ins long put one either end so there is an 11/2either side screw them through the existing plasterboard
put one or two in between and screw them, cut your plasterboard too 48x18 screw it to the 3x2 seal the joint then plaster over hope this helps

Answer 6

fix two straps of wood across the hole at top and bottom fix onto good plasterboard by screws then screw new plasterboard on the the wood