I have a in ground spa that dropped down from the decking about 3 inches. There was a hard 1″ plastic insert that broke apart when the spa dropped down the first time (see red arrow in photo). I few years ago, I tried to repair the gap by filling in with construction foam and silicone caulking, which did work for a few years. However, the silicone separated overtime, which may be from the spa dropping more and or the silicone loosing adhesion.

Everything I have found to read is about the upper decking gap and nothing about spas or pools dropping down from the concrete decking.

I am not sure what I should do. I suspect there is no permanent solution and may just have to put the foam back in and re-caulk it again?

I was thinking it may be possible to fill with some kind of flexible concrete product, assuming that exists?

I also was thinking I need so somehow put the ridged plastic strip back, but I am not sure how to attach it or where to buy it or if there is one that is wide enough, as the one that was installed was only 1″

Maybe there is a “coping” I can put into the gap?

I am certainly open to suggestions?

Thank you for your help.