Limestone pool coping is a natural and expensive-looking choice; but to keep a pool looking its finest, a certain amount of upkeep is required. Limestone is somewhat porous and a relatively soft and less-dense rock. While those traits mean it stays cooler when the summer sun beats down, it also means limestone can fall prey to a variety of maintenance issues. Thankfully, many of these can be handled by non-professionals.
Chipping and Erosion
As a softer rock, limestone can chip with hard use. Dropping heavy objects is a common way to chip away at a pool deck surface. While it is not usually a detriment to the pool, a chipped piece of limestone can be hazardously rough and an eyesore. If a piece of the limestone pool coping has been chipped, that piece will need to be replaced completely to restore the pool to looking new.
More common is that the limestone can erode with age. While this is a slow process, frequent use can wear on the stone. In time, these worn pieces will also need to be replaced.
Salt and Chemical Damage
The salt and chlorine in a pool, among other chemicals, will inevitably splash on the limestone coping. The stone should be sealed to protect against these harsh chemicals--and periodically this seal will need to be redone. Failing to do so can lead to a corroded and faded pool surface.
The same sun that causes swimmers to get sunburn beats down on the limestone pool coping. Gradually, it will fade the color of the pool deck. While not necessarily bad, the pool deck will eventually lose its original color.
If the stone has been decoratively painted, this paint will be the first part to noticeably change. Periodically the paint will need to be reapplied.
Mold and Algae
The most common, and easiest to fix, problem for pool decks is mold and algae. The wet environment around the pool deck and warm summer weather make it easy for algae and black mold to set in. This can be cleaned with a chemical solution available at home improvement stores or by power washing.