Why do some trades say you cannot paint over pva.I have done it for years without any problems.

because they cant be bothered doing it p.v.a is a primer and a sealer if done before painting will make the paint last longer

Its not like you cant. Paint drying much quicker and better on "normal" surface. You just must decide PVA or not. Never do half or just some places to avoid flashing. In that case two coats wont be enough. But...You know that. Regards

sthephen is true. some cowboy builders want to just finish the job quick and get the money and run...but that is good for us i suppose because brings more work on the market for repairs..