Carpentry and Woodworking - I need Some Help - When installing crown molding.....

I am in the middle of installing crown molding and you all have been great so far with answering questions to my previous post. I put my first piece of crown up and it looks pretty good for a first timer. The crown has no gaps up at the cieling and some small gaps on the walls. I guess a little caulk will fix that. My question is: I was able to fasten the crown to the wall using a nail gun and into stubs, but the ceiling part there are no studs. It doesn't appear that this crown is moving at all because i nailed it in on every stud but i am just a bit concerned that i am not fastening into the ceiling, does anyone have any suggestions for the other pieces i will be installing? Or is this normal? Thanks for any input.

You could nail up some pices of 1x that have been ripped to the proper width and angled on one edge to mate up to the backside of the crown molding. This would give you something to nail the upper side into. On walls parallel to the joists, hopefully you have a nailer overhanging the top plate to nail this block into. On the other walls, you can nail into the joists. Saw something like this in an issue of Fine Homebuilding a year or so ago. Maybe check back issues at the library.

Cmisti66,

It may not be a problem to not affix the molding to the ceiling. Molding is very light, and I have even recommended in cases where people know they have a lot of movement in their home to intentionally leave one edge 'floating'.

If this is large molding, a long run, or you are just concerned, I agree with 'formula' in using a 1x backer. You could also opt for a good construction adhesive -- -- or as I have done many times -- -- simply use a paintable latex caulking as the upper adhesive. It will allow for some movement and help cover over any installation sins.

Powergrab on the top and nails in the studs works wonders. Do it right the first time as the powergrab is tough to wiggle.