I am working on a ranch style house that was built with a screened in porch on the end. I have enclosed the porch and tore the wall out to the existing house. I installed T & G pine on the ceiling tying into the existing. I didn't quite get the stain to match as good as I would have liked. I thought it was dead on until I installed the boards and it took on a lighter look to it. My customer doesn't really like the darkness of the old ceiling, so rather then spending the time on trying to blend the old to the new they want me to whitewash the whole thing. So being I have never done this I thought I better look into it before I make any attempts. I do have some scrap pieces with the new finish on them that I can use to test with. It appears the old ceiling just has stain on it. The new ceiling I sprayed on a stain sealer mixture. At this point both ceilings seem to have about the same sheen to them.
So before I get myself any deeper into a mess I thought I better ask around first.
Hopefully there is a product that can be used over the existing finish.