Greenboard is another name for moisture resistant sheetrock, or drywall. The paper that covers the gypsum core is coated with wax and is a green color, hence the name.
It used to be the industry standard for moist areas, but it has been proven that it retains water which promotes mold, and now greenboard is no longer certified as a tile substrate by the International Building Code, as of Jan, 1, 2006, per 2006 IRC 702.4.2:
- “Cement, fiber-cement or glass mat gypsum backers in compliance with ASTM C1288, C1325 or C1178 and installed in accordance with manufacturers’ recommendations shall be used as backers for wall tile in tub and shower areas and wall panels in shower areas.”
Mold resistant drywall can be used in areas other than shower and tub wet areas, as it takes care of both the mold and moisture issues.
For tile a substrate, one way to go is using cement board. Hardibacker board and Durock are cement board products manufactured by different companies. There are minor differences; Durock is made with glass fibers and Hardibacker is made with wood fibers. Hardibacker 500 tile is mainly a wood fiber (cellulose), sand and cement composite panel. Due to it’s organic composition it shouldn’t be used in a steam shower area.
Durock and Wonderboard are basically inorganic sand and concrete boards reinforced with fiberglass mesh on the surfaces. Denshield is acrylic coated glass mat faced gypsum board, basically just waterproofed gypsum, and isn’t preferable in a wet shower area.
Another alternative is called Kerdi, made by the company Schluter, who also make Ditra, for floors. Kerdi is a waterproof membrane that is bonded with thinset mortar directly on green board, or plain sheetrock. It is polyethylene and has a low vapor permeance of 0.75 perms, so it can be used in steam showers no problem. It comes in a 39″ width roll, and when properly installed, water never gets below the Kerdi. Just be sure to provide a minimum overlap of 2 inches at seams between sheets.
In bathrooms, you do not use this on the ceilings, but on the walls behind the shower surround and by the sinks, but not on surfaces that will become wet, such as shower walls underneath tile.
Hanging the sheetrock greenboard alternative is the same as hanging any dry wall, except you will have protect walls from moisture. Learn how to hang the sheetrock greenboard in the bathroom. You will need some tools for this process.
Things that you need:
Sheetrock greenboard (sizes available 4×10, 4×8 and 4×12 foot lengths) (thicknesses are 1/4, 5/8, 1/2, 3/8 and up to an inch) the ideal thickness for a bathroom is 1/2 inch thick.
Nails and screws for the 1/2 inch sheetrock, the nails and screws need to be 1 1/4 inch long. Rule of thumb is a pound of screws or nails for five sheets.
Check the studs to make sure there is nothing protruding out. If there is, it must be corrected. You will a completely flat stud with nothing protruding to prevent the sheetrock greenboard from lying flat against the wall.
Use a marker to mark the outlet boxes on the floor. This will give you the idea where they are after you hang the sheetrock. Measure how far they are up from the floor and write this done as well. With another color marker, mark where the studs are. This makes it easier when you are nailing up the sheetrock.
Measure the first wall. You want each sheetrock edge to end on the stud. You want to make sure to make any cuts so that the sheet rock ends in the middle of the stud, so you can add the next piece. Start in the corner of the room and work you way to the next corner cutting the sheet rock to fit.
If you are doing the ceiling and the walls, make sure to do the ceiling first and then the walls. After the walls are up, cut out the outlets and switch boxes. This can be done with the utility knife. Follow your measurements and floor marks for this process.
After you have the sheetrock greenboard up and the outlets cut out, you can then get ready to tape the joints. This is not hard, but if you do not follow the right procedure, you could waste more time. You will need joint compound, a compound spreader and the tape.
Applied a good amount of mud compound to the joints. Add the tape over the mud and make sure it is straight and no bubbles or wrinkles. Allow the tape to dry over night before adding the next coat of mud. Mud the taped joints and make it smooth. Let dry.
Add another mud cost getting it as smooth as you can for less sanding at the end of the mudding. The finale coat is where you want to place the mud on the joint and tape, but do it smoothly and you will have minimal sanding. Let dry overnight.
Use 100 grit sandpaper to lightly sand the area. You want to get everything smooth. Do not over sand the mudded areas. Now you are ready to texture or paint.