Plastic strip right above tile breaking off


New member
Jul 2, 2019
Hi guys. New member here (go easy). So I did about an hour of research on the website, but I just wanted to be sure and provide a picture so I know exactly what to do. So the plastic strip above the tile in my pool is breaking off, which is exposing a slit that leads to the outside of the pool shell (is that right?). I think this is cantilever pool coping, but I'm not sure of the name of the strip. Anyway, all the info I found leads me to believe that this strip cannot be replaced and instead has to be filled with some kind of mortar, lest pool water seeps in and damages the shell. Yesterday there was a 7.1 mag earthquake which reached me where we are and the pool water started sloshing out of the pool and I'm sure into the slit. I'd like to take care of this issue before something else happens so that the shell doesn't damaged (hopefully it isn't already). So just to reiterate, I'm fairly certain this strip can't be replaced and has to be filled, with mortar from what I've read. If so, which kind of mortar do I use? Thanks.

One more question. I've been trying to scrape off the water stains with a pumice stone with limited success. Is there anything else (aside from sandblasting or bead-blasting) that I can use to remove these stains? Thanks.



Bronze Supporter
Mar 15, 2017
Chicago/Northwest, IL
I had the same issue. (The gap - not the earthquake, fortunately...) I used backer rod and silicone caulk to fill the void. It's my understanding the it's better to maintain some flexibility in the space and mortar would likely crack and fall out over time. I'm sure someone way smarter than me will chime in here.