Pool sealant for space between concrete and coping

Jim H

LifeTime Supporter
May 12, 2015

Hi! When we had our pool done they placed this styrofoam looking stuff between the concrete and coping. They said it's pretty standard but it looks pretty sub-standard to me...is there a better sealant to use between these spaces- something that doesn't look like its going to break down in a year or two ? Brands and where to get them would be helpful! Thanks!


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
The right way to finish that job is to cut back the styrofoam a bit and finish the gap with a flexible mastic (caulking) compound. The mastic can even be sanded after application, but before it sets up, to make it blend in with the concrete and coping. It's not "difficult" to do per se, but it does take some skill because mastic is thick and gooey and one can go from a professional looking finish to a lousy looking hack-job in a hare's breath.

If you can't get a decking pro to do the job you can do it yourself. I would just suggest you practice a lot first.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
Sometimes that Styrofoam is perforated and the top 1/2 inch will pull off rather easily, leaving space for caulk.
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