Your pool deck sits on the wettest soil in the yard.

Pool Deck Cracks or Settling: diagnosed and explained.

Pool decks fail from underneath, and faster than most concrete on a property, because the soil around a pool never really dries out. Splash out and backwash keep it saturated, drainage from the surrounding yard often runs toward the pool, and expansive clay in that constant wet and dry rotation swells and shrinks relentlessly. The deck answers with cracks working across the surface, panels settling out of level, raised edges at the joints where bare feet catch, water pooling where it used to drain, and the most telling sign of all: a gap opening between the deck and the pool coping. That gap means the deck is pulling away from the pool structure, and it deserves quick attention, because the open joint channels water straight down along the pool shell, where it erodes the soil supporting the pool itself and can disturb the tile line and coping. Many older decks were also poured with little reinforcement, so once soil movement starts, cracks propagate easily. The encouraging part is that a settling deck caught while the panels are sound is a lifting project, not a demolition project.

For the repair side of this, the concrete leveling solutions page lists every method Dalinghaus installs, including the ones that fix problems other than pool deck cracks or settling.