Loss of paint due to poor adhesion. Where there is a primer and top coat, or multiple coats of paints, peeling may involve some or all coats.
Seepage of moisture through uncaulked joints, worn caulk or leaks in roof or walls.
Excess moisture escaping through the exterior walls (more likely if paint is oil-based).
Inadequate surface preparation.
Use of lower quality paint.
Applying an oil-based paint over a wet surface.
Earlier blitering of paint (see Blistering).