Plaster walls?

[glc4]

I have a 1957 home with plaster walls. I want spray them for a knockdown look. What do I have to do for prep. before I spray over the plastert? any information would be great. Thank you GLC4

[HayZee518]

what do you mean knockdown look? texture on the walls and ceiling? ceiling only? if you want to paint the walls cracks will appear unless a skim coat is applied and there is no guarantee that the cracks will never show up! Ceiling texture will hide the blemishes in joints etc but not major boo-boos.

[Snoonyb]

Remove any loose and peeling paint, repair any cracks and nail holes,prime and apply the knock-down, prime again and apply finish.