I have a precast cistern that Ive had since 1983. It is a 3 section with 2 seams that runs horizontally around it. It started leaking a few years ago, and I patched it with hydraulic cement and painted theroseal as well. That would hold the crack seam for about a year. But here lately it only hold for about 6 months. its always leaks in the seam where a hair size crack forms. I can't tell but I think it must be moving since the crack keeps coming back. What can I use to seal it? something flexible?
Thanks for any advise.
jim
Thanks for any advise.
jim