Cracks in your swimming pool plaster can be as simple as a closed shrinkage crack or as damaging as a large structural crack. The key to plaster cracks is to properly identify the type of crack, the severity of the crack and the proper ways to remedy the pool plaster crack.
There are 3 Types of Common Swimming Pool Plaster Cracks:
1. Closed-Shrinkage Cracks
2. Open-Shrinkage Cracks
3. Structural Movement Cracks
Closed-Shrinkage Cracks (check cracks)
These cracks are normal in cementitious coatings and occur within the first 24 hours after installing new swimming pool plaster. These cracks are “reversible” meaning that they eventually seal themselves up within 24 hours after immersion. The component responsible for sealing these cracks is calcium hydroxide. These types of cracks require no remedy as they seal themselves although their presence may be detected after sealing due to dirt trapped inside the crack before sealing itself.
These types of cracks can be closed-shrinkage cracks that never sealed and are shrinkage-related cracks that did not seal themselves. Smaller cracks would need to be cleaned and filled with a cement paste, or with cement and a fine sand or other crack-filling material used in aquatic environments. Larger cracks would need a thicker paste or crack-filler.
Structural Movement Cracks
These cracks are typically due to weak points in the cementitious surface and can easily be caused by structural cracks in the concrete pool shell underneath the pool plaster layer.
These types of cracks should be identified as “working” or “non-working” cracks, in that “working” cracks are still moving or subject to moving, while “non-working” cracks have stopped moving and have already relieved whatever stress was causing the crack. If the crack is “non-working” then these can be clean and filled with a cement paste or patching compound. If the crack is “working” then the cause of the crack would need to be diagnosed and corrected before repairing the crack in the pool plaster. In some cases, “working” cracks and “non-working cracks” in the concrete pool shell can be filled and stapled together using special staples.
To repair pool plaster cracks you will likely need to drain the swimming pool or use an underwater method and material if possible. Underwater patching of cracks will likely be a temporary repair until the swimming pool can be drained or resurfaced all-together.[/vc_column_text][/vc_column][/vc_row]