Expansion Joint Filler


Gold Supporter
Jul 17, 2018
Marlboro New Jersey
I had some coping work done and the contractor removed the existing "foam" like filler that was between the coping and deck.

When the coping contractor was done they did not replace it and now it's up to me to deal with it.

What are my options now that the foam is no longer there. Do I put sand/dirt in there and then add self leveling caulk. (the same they use on sidewalks.)

The contractor mentioned for a professional job for just under $1000 they will use "Mastic" caulking. Is that worth it? They said this "mastic" caulking will adhere near the top of the expansion joint so no need for a filler foam. This doesn't sound right to me because I would think over time any caulking without the filler there it will just cave in.

Any advice is greatly appreciated as I don't want to spend $1k.

Thank you.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Foam backing rods and then Deck-O-Seal or Sikaflex on top of it.