A little history. Our pool was built last fall and they had caulked our pool in late November. It was done poorly the first try and had them come back again the next day to repair and it was questionable at that. During the winter, we experienced significant frost heave throughout the entire concrete deck and still have 1/4-1/2" raise on the deck throughout. I believe that the poor caulk job allowing water below the deck contributed to the deck heaving. In the spring (May), they came out and tore the entire caulk out and it was easily removed in 90% of the pool by simply pulling it. The employee stated "I'm suprised on how easy it was to pull the caulk out." They were SUPPOSED to come and replace the caulk and never came back. I have begun doing it myself and have read many articles on how to do it. I purchased Vulkum seal and 3/4" backer rod for the entire pool.
From many of the articles I've read, you should remove the foam that was used during the pour to replace it with the backer rod. It was easiest for me to remove the entire section of foam around the entire pool, so I now have 3 1/2 inches of void between the deck and the coping. Removing the top portion of the foam only resulted in about 1/4" of area to caulk and I wanted to make sure I had enough area to place the backer rod in the void. Can you tell me the pros and cons of adding sand to the void prior to placing the 3/4" backer rod in prior to caulking? Does it matter if there remains a void below the backer rod as long as the backer rod is tight and the caulk is done properly? I suspect that since the pool has been subjected to water drainage throughout the void since last November that I've gotten some erosion below the concrete, but since the concrete remains heaved, not sure what impact that has.
Appreciate any advice or thoughts. I plan on completing the caulking sometime this weekend.