Do you not have to cover the original
Plaster with PVA before skimming? Another builder said this is what some do and he may have used a dirty brush to put it in with?
I've just had a garage converted to play room with new plaster board etc. I have waited for the the plaster to dry and then have covered the paint with a watered down white emulsion paint. To my horror it's covered in what appear to be drip marks! These are virtually everywhere (except not in...