# Forum Home Renovation Concreting  Skimming concrete after popcorn ceiling removal

## proc1125

Hi, 
i have removed all of the popcorn ceiling in a room (this is in a condo). There are still some of the old plaster left. Before adding the new skim layer, should I sand off all the old plaster or can I just prime over it with PVA and skim coat the concrete. 
Thanks.

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