[url=http://homes.yahoo.com/news/newcomer-tops-consumer-reports--tests-of-interior-paints-192439090.html]Newcomer tops Consumer Reports' tests of interior paints - Yahoo! Homes[/url]

I once had this complete idiot in to do various jobs in my house. Everything he touched has fallen apart. The latest in the line of problems is that the basin fell off the wall because the moron siliconed it to the wall without using any bolts. Luckily I have a pedestal and it didn't break. A whole lot of paint came off the wall with it. We should have realised something was wrong at the time but we didn't and I repainted the entire bathroom with the first coat of a new paint. I came to repair just that section afterwards; I intended to scrape off loose paint and coat it with primer then continue with the paint job. Unfortunately all the paint on that wall is loose and is coming off in sheets. I have now cleared 2 square meters because no matter what I cannot paint over loose sections like that. Anyone have some input as to why this has happened? Also can I repaint just the cleared section or should I scrape the entire wall or the entire bathroom? Obviously because I have just used an entire tin of paint to paint this bathroom I don't really want to redo it all but if I have to I will so that it is done properly.