When you remove tile, you are sometimes left with tile glue stuck to the wall. This is called mastic. It is a great product when it is doing its job of holding the tile on the wall. But when you remove the tile, there it is -- lumpy, dry and hard as a rock. Removing the mastic and smoothing the wall takes science, elbow and art.
Sweep the dust or debris from the area where the tile was. Vacuum it. Scrape the area with a putty knife to knock off any loose mastic. Avoid digging into the wall when you do this.
Apply the mastic remover to the wall area as directed on the bottle or jar. Let it sit the suggested amount of time. This will vary depending upon the strength of the product and condition of the mastic. Check the wall every 10 minutes to make sure the remover is not drying out.
Scrape off the mastic remover with the putty knife. Let the wall dry. Spackle any holes in the wall. Let the spackle dry overnight.
Sand down any rough edges in the spackle with the sanding block. Wash the wall with mild soap and water on a damp cloth to remove the dust from sanding.
Roll a thin coat of fast-drying, stain-sealing primer onto the wall with the 1/4-inch-nap roller. Let it dry thoroughly.
Dilute the all-purpose joint compound, and roll it onto the wall using the 1/2 inch-nap roller. Dilute small batches at one time if you are covering a large wall area so the joint compound does not dry out before you are done.
Smooth the joint compound with a squeegee before it dries, working from the top down. Wipe off the squeegee with a damp cloth to keep it clean of joint compound between strokes. Continue with the squeegee until you accomplish a very smooth. Let the wall dry completely. Run the sanding block over the wall to finish it off for painting.
Determine when the tile was put up. If it was before 1980, consult a professional because some tile adhesive, called mastic, contained asbestos at that time. Do not try to remove this tile adhesive yourself.