We are redoing a small bathroom and I want to redo the old tile and also add some additional tile around some of the other walls. We are planning to use cement board around the tub, but do I need to rip out existing wallboard around the vanity and other walls where I want to add new tiles and replace it with cement backer board? Or should I just add the cement board on top of the existing wallboard in the places I want to add new tile ( I was thinking about maybe tiling halfway up some of the other walls). Thanks!
Over cement board, use thinset to bond the tile. Over painted drywall, use mastic for tile bonding. First, clean and sand the painted drywall to promote tile adhesion.
Cement board is only needed around a tub or shower, Adhere the tile with a modified thinset adhesive. Use mastic (glue made for tile) on the existing drywall rather than thinset on the rest of the room.
First take some rough sandpaper like an 80 grit to rough up the wall that is painted, then use a mastic type adhesive like Acrylpro ceramic tile adhesive from Home Depot. It is $6 for a quart or $13 for a gallon. Use the correct size trowel suggested on the bucket for your tile size. Follow the directions and you will be fine. You would only use Hardibacker or Durock in a shower or bath tub enclosure where heavy use of water goes on. Then you would use the screws made for that product and use thinset adhesive instead of mastic.
