lfrazer98 wrote:I was just thinking that we might have too imperfect of an outer rail to just used a caulk.
For larger gaps, a caulking bead backing can be used. Basically they are round foam gap fillers of various diameters, that the caulk is applied up against. They allow for greater joint thicknesses, and greater flexibility.
Another option would be to use a thicker foam strip made out of a lighter weight foam. Areas that need to be compressed can be, while the larger gaps are still filled. I'd use a closed cell foam to keep water absorption down. Condensation running down the walls on the inside will soak into an open celled foam. A bead of caulk at the floor to wall joint may keep the water out.
With all caulks, jointing surface prep is important. Clean using the recommended method, and don't touch with your oily fingers after cleaning. Even if your fingers don't feel oily, they still are oily enough to cause long term problems.