Can Wall Bulges on Fiberglass Pools Be Fixed?

Fiberglass Pools

• Fiberglass pools exist as prefabricated shells; they consist of small glass fibers, or fiberglass, the pool shell's primary material ingredient. As a material, fiberglass possesses the strength and durability required to hold large quantities of water. While fiberglass makes for a sturdy material, strength capacities vary depending on the manufacturing process.

  The installation of a pool can have dramatic effects on how well a fiberglass shell holds up. Improper installation may cause bulges to appear on pool sidewalls over time. If left unattended, these areas can eventually turn into cracks and begin to leak. Conditions that cause bulges to form often involve a pool’s water level and the underlying groundwater level.

Pressure Imbalances

• Pressure imbalances in a fiberglass pool develop when a change in the pool’s water level occurs, such as when draining a pool. More often than not, pool installers use sand as a foundation material when laying a pool. As some land areas may experience high groundwater levels, a sand foundation can quickly become semi-liquid as groundwater levels rise. These conditions create a pressure imbalance between the ground, the pool shell and the water inside the pool. Ensuring water remains at the manufacturer’s recommended levels can help reduce the likelihood of bulges forming along pool walls.

Patch Repairs

• Patch repairs for bulges in fiberglass pool walls involve cutting out the bulge area, placing plywood material behind the opening and filling the opening with polyurethane foam. The entire pool wall surface will then require a new fiberglass coating. In order to make the repair, you must drain the pool or else the backfill, or wall foundation material, will spill into the pool. Ultimately, the strength of the fiberglass shell will determine how long a patch repair will remain intact.

Sump Drain System

• The foundation materials most often used for fiberglass pool installations include sand and gravel. Most manufacturers recommend the use of sand, according to the Pool & Spa News website. Nevertheless gravel can provide solid bases for pool bottoms.

  The use of a sump drain system in areas known to have high groundwater levels can help prevent pressure imbalances from developing between pool walls and sand foundation materials. Installing a sump drain system alongside the deep end of a pool’s exterior wall may help prevent existing wall bulges from turning into cracks.