Here is a poll of sorts to see how many builders always insist on the isolation of the bond beam via a mastic joint with foam as compared to those which say a) never or b) depends on situation. I have seen many pools with both methods and am just wondering who feels they lean toward which way and why? Even if you are a not a PB and at least own a IG pool, does your pool have this expansion/mastic joint where the pool deck meets the bond beam/coping?