Mastic around Spa


New member
Aug 27, 2019
Allen, TX

Im a new home owner with a pool and still figuring out all the various components we have.

While I do that, one thing I spotted a few days back was the mastic around the spa needs to be replaced. After reading several posts here I know that I require a grout removal tool, all purpose sand, sifaflex Self-Leveling Concrete Sealant and a closed cell backer rod.

Once I remove the old mastic, I see sand below it- do I need to remove and clean that our before I put in the new backer rod or should it go on top of the sand?

Appreciate any help!


Jandy Aqualink RS PDA Pool Digital Assistnat
FNS Plus Vertical Grid DE Filter


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Clean the expansion joint down to the bottom of the coping. The objective is that there is flexible material with the backer rod or mastic pressing against the coping.