Those swimming pool cracks you see in the surface of your pool are often just on the surface of the pool body, a surface crack in the plaster coat, and they might not run all the way through the pool body itself. The majority of in-ground pools are constructed of 6 to 8 inches of gunite or shotcrete, a concrete type of material that is spayed over rebar steel reinforcement. Contractors often refer to in-ground gunite and shotcrete pools as concrete pools, verses in-ground fiberglass or vinyl lined in-ground pools.
The top edge of a concrete pool body usually has an extra wide area (about 12 inches) of gunite or shotcrete that adds more strength to the top rim of the pool shell; this top area is called a bond beam. Overall, in-ground concrete pools are usually very strong and last for many years, especially with proper maintenance.
Not all pool cracks mean that the pool is leaking; for instance, shrinkage cracks are normal; they are shallow and just part of the curing process that occurs when the pool is first shot with gunite or shotcrete.
If a crack is a structural crack, it is that the pool is leaking or will be leaking in a very short amount of time. These cracks occur in the actual shell of the pool and may appear in various locations. Cracking can take place vertically or horizontally. The majority of structural cracks running through the concrete will also be mirrored through the plaster coating and even the tile area over the bond beam.
Surface cracking is basically observed in the plaster and for the most part is not a leak issue. These surface cracks are normally thought of as maintenance or repair types of issue. Don’t jump to conclusions that surface cracks are a notification of structural cracks, get a proper leak detection or pool inspection to know for sure.