Armstrong ceiling tiles?
I'm working on a 1920's house that has has ceiling tiles installed at some point. They're in good shape, but I've torn out some closets, etc., and have to add some back in. I can buy tiles that match at Lowe's, but I have not clue how to install them. I know they interlock---but what keeps them against the old, bead-board ceilings? And NO, I do NOT want to go back to the bead-board at this time (Maybe later!)