Mortar is acceptable for application over concrete, masonry, brick, backerboard and gypsum wallboard. These surfaces must be prepped before applying bonds that were thinset to be sure the material.
Put on safety glasses and rubber gloves. Mix 1 teaspoon trisodium phosphate in 1 gallon of warm water. If you’re washing a wall that is large, you may need to double the cleaning solution in two gallons of warm water.
Wash painted walls and tiles using a sponge.
Scrub the walls using a sponge soaked in clean water, and then leave the area to dry.
Put on a dust mask. Sand painted walls using an sanding sponge to remove the sheen. Wash off the residue with a tack cloth.
Patch cracks and holes in the wall. Drywall can be patched with drywall joint compound, whereas cement and masonry surfaces should be patched using a cement-based patching compound.
Sand patched areas smooth using sandpaper, such as 220-grit, and wash the wall using a tack cloth to remove sanding dust.
Vacuum sanding dust from floors, counter tops and other surfaces, and secure plastic sheeting with painter’s tape to areas surrounding the walls to protect flooring, trim, cabinets and other surfaces which will not be covered with vinyl.