PLASTER POOLS

A beautiful swimming pool can be a wonderful addition to your home and a place to spend many happy hours. One of the benefits of having a plaster pool is that it is possible to have varied pool shapes and customized looks. However, unless you have experience, you need to hire a good plasterer (see choosing a contractor), who is adept at plastering swimming pools, because the work is different than plastering walls and ceilings and requires special plaster mixes. So, whether you hire a contractor, or do it yourself, here is some information that will help you create your backyard water oasis.

A few days before the plasterer is called in, the base foundation (i.e.cement, gunite, shotcrete) is installed. When the plasterer arrives, he should start by wetting down the sides of the pool with water until the walls are thoroughly dampened before applying a brown coat. Although there are several mixes out there on the market, one common mix for the brown coat is 1 1/2 bags of fine white marble dust, 1 1/2 bags of course white marble dust, l bag white cement and possibly some calcium chloride solution to accelerate the setting of the material (this is dependent on ambient temperatures). The natural plain white finish of the plaster will give the pool an alluring light blue color when it is filled with water. The mixing of plaster should be done in a clean power mixer. The brown coat is first applied to the walls and the coved area between the wall and the floor. The thickness of this coat should be about 3/8” and troweled fairly smooth. When the brown coat is fairly stiff, the plasterer will apply a “tight” finish coat over it. Tight is a word that plasterers use to describe a finish application where they push harder against the wall, spreading the finish thin and leaving no trowel marks.

The mix for the finish is very similar to the brown coat but with a little more cement (1 ½ bags of white cement instead of only one bag).Usually two men work together to apply the finish so that it can be done quickly and maintain a good finish. The floor and the steps are different than the walls of the pool, in that they have only a one coat application. The brown coat is applied to the floor a little thicker (1/2”) and when it hardens enough to walk on, it is wet troweled twice. Last, the brown coat is applied to the pool steps the same as the floor. When the plastering of the pool is complete, it is filled immediately with water, as quickly as possibly, but without damaging the surface of the plaster. A large pool will need to be filled with a water truck, but small pools may be filled with a garden hose if it can be done quickly enough. When the pool is about half full of water, test the pH, and adjust it. Do not add chlorine for 3 days (72 hours). Although most of the curing will occur in the first month, the pool plaster will continue to cure over the next year.

Once your plaster pool is complete, you will need to care for your plaster pool by checking and maintaining water conditions. The pH of the water is important because extreme acid or alkaline conditions can affect the plaster. For example, crystals can appear on the plaster surface under alkaline conditions and acidic water can cause deterioration of the plaster finish. Chemicals to maintain water balance are important to the life of your plaster, but be sure to dissolve all chemicals before adding them to the pool as concentrated chemicals can damage and cause color changes in the finish. In the winter, it is best to cover the pool with insulation and maintain the temperature above freezing to avoid the expansion of ice cracking the plaster. However, if the pool is not correctly maintained, it can be repaired. The pool can be acid bathed and polished to renew its finish. If there are areas that have become delaminated or loose, they should be removed and repaired. Another option, but probably a more expensive alternative, is to clean the entire surface with a pressure washer and apply a new coat of plaster.