I've always heard, and used, the idea that caulk should be used instead of grout when two surfaces intersect. (In a corner, where wall meets floor, etc.) A neighbor just had a bathroom renovation done, and I had looked in a couple of times during the process. In the shower area they had placed the waterproof backer board along walls and floor, and the shower pan had been lined with a vinyl (?) membrane, which extended approximately 6 inches up each wall. Over the weekend, after it was all done I noticed that they had used grout in both corners and wall/floor intersection. How serious a problem with that be? (And if it's a bad problem how I tell my neighbor?) Any advice to give him? As always, thanks in advance.

I've built a 6' wide partition wall that I'm looking to secure to existing sheetrock ceiling. The wall is free standing and has nothing attached on either side of it. Wondering how I can secure the two ends of the top plate to the ceiling since there is no ceiling joist directly above either end of wall's top plate. The ceiling joists run perpendicular to this new wall I'm adding. Was just going to locate the joists and shoot nails the top plate existing sheet rock and into joists. Do I need to remove the existing sheetrock to expose the joists and then attach 2x4 blocking the between the joists?