UV light and weather
UV light and weather conditions affect every type of pool interior. One only needs to examine the corner of an older vinyl-liner pool that has been subjected to direct sunlight to see the damaging effects. Often, the rest of the vinyl is perfect, yet the area above the water line can become discoloured and brittle to the point of failure.
Sunlight striking the vanishing edge dam wall of a tiled or aggregate pool can also lead to failure, particularly when combined with poor structural integrity and waterproofing. UV light will practically cause every material, with the exception of some tile products, to fade over time.
Extreme temperature variations can also wreak havoc. Ideally, most pool interiors are installed in moderate temperatures between 10 to 27 C (50 to 80 F). Temperatures above or below this range can prevent a pool’s interior from being finished, e.g. high temperatures can limit the application of glass tiles. The combination of direct sunlight and heat will also accelerate curing times; therefore, using a tent to enclose the project is an advisable alternative. Further, extreme temperatures can also affect the safety of the installation crew working at the bottom of the pool.
In contrast, cold temperatures can make vinyl liner installations more difficult as the lack of stretch in the material will make fitting corners, wall coves, and stairs quite difficult.
On plaster finishes, cold temperatures call for special precautions, such as heating the area to be plastered or the materials to be used, including the water. Using additives such as calcium chloride (CaCl2) can accelerate the plaster’s set time, while the improper handling of plaster in cold weather can lead to failure, particularly if it is allowed to freeze.
Freeze/thaw circumstances are perhaps the worst environmental condition a swimming pool interior can be subjected to. The waterline and coping normally draw the brunt of the damage, while the improper use of adhesives, combined with poor drainage, installation and material choices, could also lead to failure. For example, ice build-up can damage plaster pool steps; therefore it is a good idea to install durable tile on the upper stairs or shallow lounging areas, leaving the less expensive plaster finish for the balance of the pool interior. Winter conditions have surprisingly little effect on the pool interior below the ice penetration level.
Rain, snow, and intruding water from sprinklers, sloping decks, roofs, and dripping tree leaves can also cause interior finish problems. Limiting the amount of water that reaches the pool interior during the installation process will result in a more durable, esthetically pleasing finish. Construction tenting, pumps, and stopping installation, are all viable options depending on the infiltration severity.
Intrusions from nature, including leaves, grass clippings, windborne debris, and bird droppings can also result in cosmetic flaws on the interior surface. Vinyl pools have the opposite problem as every tiny speck of debris is magnified under the vinyl liner. A simple lady bug left beneath the liner will look like a small rock when viewed underwater.
Structural integrity
The structural integrity of the pool interior’s subsurface greatly affects its longevity. For instance, fibreglass pools are particularly susceptible to backfill settlement, thus the resulting shifting of the pool can cause the structure to bulge or go out of level, stressing the interior finish to the point of failure.
Vinyl pools built with sand or Styrofoam floors can look unsightly in a few years as heal prints in the Styrofoam or shifting of the sand can become readily visible below the surface. On rare occasions, plant material, such as tree roots, can penetrate a poorly constructed concrete or grout pool floor, visibly and mechanically impacting the vinyl as a result. Should the structure of a concrete pool fail, so too will the interior finish. Improper shotcrete techniques and the use of rebound in the shell will also result in failure over time.
Water penetration
Water penetrating the pool shell, combined with poor drainage conditions, will cause trouble for any pool installation. Failure to provide adequate drainage via gravel bases, sump pits/pumps, drain to daylight or other standard construction methods may cause the pool’s interior surface to fail. It is quite common for vinyl liners to float, causing unsightly wrinkles and bulging at the base of the pool walls. This can also be caused by leaks, which is exasperated by poor drainage around the pool shell.
Fibreglass pools can shift or pop out of the ground from excessive ground water conditions that are not controlled by sufficient drainage techniques. All concrete pools can benefit from the installation of drainage wells, and sub-shell drainage systems. Keeping water away from the inside and outside of the concrete shell is desirable. Concrete is not waterproof; therefore, the pool’s interior finish and longevity are greatly enhanced by the use of adequate drainage and waterproofing techniques.
