Flexible Grout Between Coping and Deck

[Michael1]

There is a white substance between the coping and concrete desk that looks and feels like grout but is flexible. It is starting to crack, and I want to replace or repair it.

Anyone know what this substance is, and where I can buy it? Any tips on replacing it?

Thanks!

 

[Rancho Cost-a-Lotta]

Its probably Deck-O-Seal. I believe it starts out as a thick liquid and dries to a pliable solid. Getting the old stuff out is the tough part of the job.