Crazing is a network of tiny cracks on the surface of paint or plaster. The surface of the walls will resemble antique pottery. There are two ways that a bathroom wall will craze. Each requires a particular process to fix the problem.
Paint, Plaster or Concrete?
There are two situations for crazing on a bathroom wall. One is if the walls are plastered or have tiles applied with concrete adhesive. The other is if the walls are painted. Paint crazing is much easier to fix than concrete crazing.
Paint crazing usually occurs when a new layer of paint is applied before the previous layer was completely dry. It can also occur if the wall was not primed or if the wall was moist when the paint was applied. Crazing may also occur if you use an oil paint over a latex or acrylic paint or vice versa. To fix the wall, remove all the old paint, sanding the walls down until they are bare. Clean the walls with a damp cloth and allow to dry. If the wall is damp, you will need to apply a waterproof primer. If the wall is not damp, use a regular primer. Allow the primer to dry for 24 hours. Follow with a coat of regular paint. Allow each coat of paint to dry for at least 6 hours.
Plaster and Concrete Crazing
Plaster or concrete crazing is much harder to fix. The surface must be sanded down to below the level of crazing. Usually a power sander is necessary. If you have tiles on top of the concrete or plaster, use a chisel to remove the tiles. Once the crazed plaster is sanded away, clean the surface with a damp cloth. Reapply the plaster following package directions. The best way to prevent crazing from recurring is to keep the surface of the plaster damp for three days to allow the plaster time to cure. Use a spray bottle to wet the plaster three or four times a day. Apply a sealer after the curing process has ended.