Patching drywall and damaged plaster needs to be done before installing bathroom wall tile and kitchen wall tiles if you want your tiling job to look professional and to last.
Before tiling a wall it should be straight, flat and plumb. You should remove wallpaper or any other wall covering before checking for and repairing any structural or surface defects, such as loose drywall or damaged plaster.
If your wall is covered with a glossy paint, do not use chemical stripper to remove it, as stripping paint is not necessary. It's best to simply apply a de-glossing agent that's compatible with thinset tile adhesive over the paint, because The chemicals found in paint strippers could leave a residue that will interfere with the tile adhesive.
Before installing bathroom wall tile or kitchen wall tiles check the condition of the wall structure. You can do this by pushing it in between the studs. Then drive drywall screws into the studs where drywall or plaster have come loose. Look for bows in the wall and crumbling damaged plaster, then fill in the depressions, remove loose materials and repair holes.
You could simply install your bathroom and kitchen wall tiles right over the old tiles, but it's always safer to remove old tiles before tiling a wall with new ones. This is especially true when tiling wet locations, such as a shower or tub surround.
Always remove old bathroom wall tile in these areas and install a new watertight tile underlayment to install your new bathroom wall tile to.
Your first step for preparing for tiling a wall most likely will be in giving your walls a little TLC. You will need a little vinyl spackling compound, fiberglass mesh tape, and joint compound, to get the job done for repairing damaged plaster.
You can fill holes to plaster with vinyl spackling compound, and cover cracks with fiberglass mesh tape and joint compound as shown to the right. This can be as simple as taping a joint between sheets of drywall.
if your plaster is severely pitted and crumbling, or severely cracked, you can remove it by beating against it with a hammer, to free it from the wood lath below. Then pry the lath off with a crowbar.
This method is a backbreaking job that requires hanging plastic over doors so the thick clouds of dust don't fly all through the house, and where you'll also be shoveling out hundreds of pounds of debris,
Thank goodness there's an easier way. You can simply install 1/4 inch of sheet-rock, right over the top of the old plaster. Make sure you use sheet-rock screws that are long enough to go through the drywall,the damaged plaster, and the lath. The screws should also sink about 1 1/4 inches into the wall studs.
In the case, of patching drywall dings and dents, simply use vinyl spackling compound. If you have holes in your drywall around the size of a quarter, use fiberglass mesh tape and joint compound. If you have bigger holes than this, follow the steps below.
Use a pencil and a framing square to draw a rectangle around the damaged area. Use a drywall saw, and cut along three sides of the rectangle. Score the face of the forth side with a sharp utility knife. Snap the drywall, and cut the back side.
Insert a scrap piece of wood into the hole, and make sure it stretches across two sides of the rectangle. Use drywall screws and a cordless drill, with a Phillips bit. to Fasten the piece of wood to the existing drywall, on each side. Be sure to countersink the screws.
Cut a replacement piece of new drywall, to fit your rectangle, reducing each dimension by 1/8 inch, to ensure that it will fit. Test your fit, and shave your edges if necessary, with a drywall rasp.
Once your fit is right, Use drywall screws and fasten your new rectangular sheet-rock, to the wood. Don't use joint compound, as the tile adhesive will dissolve the joint compound. This will cause bonding problems.
If the sheet-rock joints are tight, there's no need to fill them. If you do have gaps, it's better to use fiberglass mesh tape, and then apply one thin coat of the tile adhesive you will be using for installing your bathroom or kitchen wall tiles.
In some cases patching drywall or damaged plaster may not be enough. Your walls may be too damaged to simply patch up the problem. If this is the case you'll need to Install new drywall sheets
If you will be tiling over freshly installed sheet-rock that's been taped but not painted, or over repairs made with joint compound or spackling compound, you'll need to apply a coat of latex primer over the surface of only the joint compound or spackling compound.
This will prevent moisture in your tile mastic or thinset tile adhesives from dissolving the water soluble compound used on the sheet-rock. It also ensures proper adhesion.
Once your done patching drywall and damaged plaster, you're ready to begin working out your wall tile patterns for laying your bathroom or kitchen wall tiles.