MY girlfriend is using a 10' piece of 4 PVC to make a cat tree. About half way up, we put a wye joint in to make a shelf. The post will be fixed to the floor and ceiling. The problem is that the post flexes back and forth at the wye joint. I used silicone, but it didn't help the movement. Is there some kind of expanding caulk I could use? Any other ideas on how to keep it stable?
I'm guessing that you haven't installed it yet? When you attach it firmly to both the floor and ceiling, it should become very stable. I don't think that you'll have to add any structure. (Unless she has a really big cat...)
