With composite (fiberglass) technology still relatively new to Virginia and Maryland, there are many misconceptions regarding the differences between composite and concrete pools. One of the biggest of these misconceptions is the belief of many people that concrete makes for a much stronger and permanent swimming pool.
To understand strength and longevity in this case, one must realize that the "rigidness" of concrete doesn't necessarily mean it is stronger, nor it will last longer. In fact, this rigid inability to "flex" characteristic of concrete is one of the leading reasons for severe cracking in swimming pools. In Virginia and Maryland, expansive soils like clay can wreak havoc on a pool's structural integrity. With such conditions present, composite pools are ideal for those looking to maximize the lifetime of their swimming pool. To understand this further, we are going to analyze a recent article published in the Pool and Spa News magazine, entitled "Gunite Troubles." Each month, Pool and Spa News, one of the most respected magazines in our industry, does a case study on common problems found in the structure of swimming pools.
The following paragraphs include excerpts from this article, found on page 44 of the magazine:
"....This rectangular-shaped, gunite swimming pool was built in 2003. The following year, cracks began to develop in the sidewalls and benches. Within a few months, severe cracking had formed in all four pool walls, benches, and steps as well as at the two skimmers and into the pool floor."
"The pool was built in an area with expansive clays, which wreaked havoc on other nearby pools and patio flatwork."
Not only were the soils a problem in this case, but also the gunite had issues as well.
"Jagged, disjointed cracks that do not intersect the bond beam often are the telltale sign of poor gunite workmanship...The cement truck probably ran out of material or got jammed, while the sand truck continued to feed the hopper (pool's slope) for a short period of time. We suspect the crew kept on shooting material until they could get their cement feeding again. Though it was probably a small, isolated area, a large crack had developed."
Once the engineers had isolated the problem, they offered a two-step solution.
"The gunite shell was weak and the soils in the area were expansive, so we concluded that the pool most likely would sustain additional cracking in the future...First, we prescribed epoxy injection for the existing cracks. The pool was then resurfaced with a fiberglass coating. Fiberglass is more flexible than plaster, so any additional gunite cracking would be less likely to propagate through the surface. Two years after the repair, we have received no report of further problems."
This article is a perfect example as to why fiberglass is the fastest growing branch of the inground swimming pool industry. This is also why most manufacturers offer a lifetime warranty on the pool's structure. With its controlled environment, the factory can regulate all aspects of construction as to ensure the product's incredible tensile strength, which differs greatly from the weather and equipment obstacles of gunite/concrete pool installations. So whether you are looking to fix an existing concrete pool, or are in the market for a low-maintenance pool to last a lifetime, composite is the right answer.
