Gunite – Concrete Construction
Gunite swimming pools are a popular choice in much of the United States. To build one of these pools, the construction crew digs a hole, puts the plumbing in place and assembles a framework grid with steel reinforcing rods (rebar). The rebar rods are spaced about 10 inches apart, and secured together with wire. When the grid is in place, the crew sprays a heavy coating of gunite, a mixture of cement and sand, around the rebar.
The sprayer unit combines dry gunite mix with water just before spraying — this produces the wet concrete material. The crew trowels the gunite smooth and lets it sit for a week or two before applying a smooth finish to the rough surface. The most popular finish is called plaster (actually a mixture of cement and marble sand), but a lot of people finish their pools with special concrete paint or pebble surfaces. Gunite pools can also have tile, exposed aggregate or even fiberglass finishes. Gunite pools are highly durable when constructed in warm climates, and they can be built in any shape or size. Gunite pool owners can also choose from many plaster finishes or pebble applications, allowing for maximum creativity.
Advantages of a Gunite Pool
- Many industry experts agree that a concrete pool is still perceived by home owners as a more durable construction method and some clients believe the gunite pool is more prestigious. Some warmer climates see the gunite pool as the number one building method for residential construction and almost all commercial construction is gunite.
- The durability of the structure and surface material in the gunite pool is good. Impact resistance and the lack of a liner contribute to gunite pools being used in a commercial environment where vandalism is a concern.
- Gunite pools are designed and built on site, and as a result, the design possibilities are nearly endless. Fiberglass pools, on the other hand, are prefabricated to a specific shape and then brought to the site in a single piece to be dropped into the hole for the pool. Additionally, gunite pools are very sturdy and because of the steel framework, retain their shape over a long period of time.
Disadvantages of Gunite Pools
- Because all the work is done on site and time must pass for the concrete to cure, it takes as much as 2-3 months or more to build gunite pools from scratch. With a fiberglass pool, the excavation can begin at the same time that fabrication of the shape is taking place. The pool arrives in a single piece and is lowered into the hole. The installation time for a fiberglass pool can be as short as 1-2 weeks. Vinyl construction will be much quicker as well with 3-5 weeks to complete the project.
- Many swimmers and children find the rough bottom in a gunite pool to be very abrasive and uncomfortable. It is not uncommon to scrape and or irritate your feet if the swimmer is in the pool for long periods of time and sitting on the pools steps or benches will certainly snag a swim suit.
- While concrete pools in the Mid-West cost more than any other construction method, that’s not always the case in some southern regions. What is more certain is that maintenance and energy costs are much greater with gunite pools. There is additional maintenance needed because the pools surface interacts with the water and can be a breeding ground for algae. Additionally, a plaster finish that is applied to concrete pools must be reapplied about every 7 to 10 years. Also, frost in colder climates can affect concrete pools requiring frequent surface repairs.
- Fiberglass pools win the battle in ease of maintenance as well. Concrete pools require maximum use of the pool’s filter because of metals and alkaloids that leech into the water through the plaster finish. Fiberglass pools also do not require as many chemicals over time because the surface of fiberglass is nonporous.