Expansion Joints and deck cracks! Why should you care?
Most people think the spaces between their concrete deck is just that, spaces. Not true, these are expansion joints there for the expansion and contraction of the concrete in hot and cold days allowing your concrete slabs to move independently without cracking.
These joints are generally filled with a pliable substance called mastic. Sometimes the pool installer puts in deck strips that are plastic white pieces that are designed to be removed and filled with mastic, as step that sometimes is forgotten.