Zinsser Gardz is a high performance sealer that can repair damaged drywall or lining paper, it can also eliminate bubbles. This primer can also be used to seal skim coats of plaster, can be used to prime drywall/plasterboard giving it a hard and durable finish and it can also be used to seal old wallpaper residue. Zinsser Gardz really is a useful product when doing decorating projects or home improvements.