Unless the surface is chalky this will help bind the surface.
Sealing bathroom walls before painting.
Clean the gaps with sugar soap before you fill as any dust could stop the filler sticking to the wall.
If the painted surface of the wall is flaking simply scrape the flaking paint from the wall.
Your clear sealer urethane sealer for ceramic or porcelain or masonry sealer for natural.
If your walls are newly plastered here s what you need to know before painting over them.
You first need to seal new plaster to make it less absorbent and to help the topcoat adhere.
If the plaster is showing after scraping flaking paint simply coat with a 1 part pva and 5 part water mix to bare plaster then face fill with quality filler toupret interior.
Previously painted walls do not usually require a primer but kitchen and bathroom surfaces have been exposed to high humidity which may cause the next coating to cover unevenly.
Let the filler to dry then smooth down with a fine sandpaper.
6 apply the primer and sealer with a paint roller in a v shaped pattern.
Take your flexible filling knife and push filler into the gap until smooth with the wall.
Apply low tack painter s tape to the walls at the edge of the ceiling to protect the walls from the primer and sealer.
Never really sealing the wall.
Finally sealing the painted bathroom tile protects your project from grime scuff marks and scratches.
Do prepare your work area before caulking the bathroom.
Without primer the wall will tend to absorb coat after coat of paint.
Primer is less expensive than paint and seals the wall.