Chris Plastow
This could be two un related problems but should be treated as one! Always start with the outside. Remove all the flaking/bubbling paint. Treat the patches with alkyde resistant primer. Coat the whole wall with pure acrylic paint. The wall will dry at 1mm per 24 hours, so this could take 240 days! The interior also requires a pure acrylic paint. Acrylic is waterproof but allows minimal drying through its surface. Do not expect results for a year!
