I don't know what to do. We hired a painter to paint the outside of our older home. After scraping he applied a oil primer and then oil paint (never thinning). After 3 years there is mildew and lots of places that have peeled up. I need to rescrape then what. After i fired the painter the next one put a oil primer and latex paint on. No problems whatsoever. Can you put a latex primer over a oil paint. Thanks.