This stuff is made for lining shower stalls and the like. I used it once in a basement renovation and found that GE II did stick to it but I had to remove a shower valve cover that was siliconed to it and found it pealed off pretty easily. I wouldn't trust that particular silicone to provide a joint that would hold up to water pressure. Maybe others would, but GE II pealed right off 2 weeks after it was applied to a surface that I had cleaned with alcohol prior to application.