Painted or Textured Drywall
Scrape away any loose or peeling paint. Scrape the wall to remove any texture and to create a flat surface. Patch any holes or cracks with spackling compound and sand the entire surface with medium-grit sandpaper. Vacuum to remove dust. Remove any remaining dust, oils and grease from the wall with TSP (tri-sodium phosphate) or an ammonia-based cleanser. Let the wall dry completely before beginning tile installation.
