Peeling paint

Paint peels when it is no longer bonded to the surface underneath. The most common causes are moisture pushing out from inside, such as rising dampRising dampMoisture from the ground that climbs up inside walls through the pores of the materials. It shows as stains, blown render and salts at the foot of walls., a leak or condensationCondensationMoisture in the air turning to water on cold surfaces such as windows, outside corners and ceilings. It is the most common cause of mould indoors. in bathrooms and kitchens, and poor preparation: paint over dust, over a greasy or glossy surface, over crumbling renderRender (plaster)A layer of mortar (sand, cement or lime, and water) spread over brick or concrete to give a wall a straight, sound surface ready for paint or tiles., or without primerPrimerThe thin first coat that goes on before the main material. It binds dust, seals the pores and helps paint or waterproofing stick firmly. where it was needed.

It usually starts with blisters that then burst and lift. Underneath you often see a white powder, the saltsEfflorescence (salt deposits)A white, powdery or crystalline crust on the surface of a wall. It is salts carried by water through the masonry, left behind when the water evaporates. left behind as the water dries out, or render that crumbles.

Paint over it and the new paint comes off with the old. Anything that is not holding is scraped off back to a sound base, the edges with the sound paint are filled and sandedSandingSmoothing a surface with sandpaper or a power sander to remove bumps, loose old paint or gloss, so the new paint or varnish grips well and comes out smooth., and the surface is primed. If the cause is damp, it has to be found and stopped first.