Laura -- well I discovered something I didn't know today. Doors in my house are hollow. John knew this already but I didn't believe him. I mean after all it is a door, it looks like wood.......
In any case, we were trying to put up robe hangers on the door and John drilled in to see if he could get a molly screw or something like it to work to hold weight. It didn't work. sigh.... Any way, I was helping him take the plastic casings back out and knocked it in instead. It rattled all the way down to the bottom of the door. Oops! So I guess our doors are hollow.