Just got the last of the ugy Ivy wall paper off my kitchen walls. They seemed to have pasted the wall paper directly to the dry wall, so I ended up taking up a fair amount of the dry wall paper in places. I am assuming I need to fully skim coat the walls now, as I want to paint. Some on this forum seem to indicate you need to prep with Gardz or some such product BEFORE applying the skim coat? Is that correct? It seems odd to me. Why not just sand the walls, skim coat and then prime? Also, do I need to wash the wall with Dirtex (or some such product) or is this not needed if I plan to skim coat?

Thanks