Shotcrete is an all-inclusive term to describe the spraying of concrete, which can be done through a wet or dry mix process. Gunite refers to the only dry mix process of shotcrete during which water is injected immediately prior to application causing the concrete to mix in midair and then it splatters against the surface. A wet mix shotcrete process, on the other hand, involves a mixture that is combined at the concrete plant before being transported to the site and pumped.
Both wet mix and gunite are referred to as “free form” applications of concrete which enables the pool to be designed in any shape or size. The concrete mix formed from these two is dry enough to be applied to vertical surfaces like pool walls.
Shotcrete is often referred to as “wet mix” because the concrete mixture is combined at the concrete plant before being transported to the site in concrete trucks.
- There is no mess to the environment as the concrete goes directly into the pump and straight to the application site.
- Shotcrete will result in a stronger and more watertight pool when used properly
- The lower volume of water results in fewer joints in the pool between concrete sections, which is typically a good thing as you want to typically minimize pool joints
- Higher compressive strengths in the range of 6,000 to 7,500 psi
- Free form application makes it possible to build strong pools in any shape
- Need a skilled pool expert to install and there are less shotcrete experts in comparison to concrete pool experts
- More expensive than gunite. Approximately $500 more per pool but well worth it!
Gunite on the other hand is referred to as “dry mix” because the water is not mixed in until application meaning that it mixes in midair when it splatters against the wall. Result is a drier concrete mix.
- Has a smoother surface than wet shotcrete
- Highest compressive strengths typically between 3,000 and 4,000 psi
- Messy to environment. Sand is dumped in the street and loaded with a tractor into the gunite rig. Public Works departments are not happy with this technology.
- Difficult to control strength of the mix in hot weather.
At Sunset we switched over to wet shotcrete 15 years ago and love using this process to build and remodel pools as a leader in our field.