Gunite vs. Shotcrete In The Concrete Pool Construction Process

If you’re considering building a new concrete swimming pool, then chances are you’ve heard the terms “gunite” and “shotcrete.” They refer to two different methods of applying concrete, but how do they differ, and which one is better?

In this article, I will describe the concrete pool construction process with a focus on gunite and shotcrete applications before diving into the pros and cons of each.

Main Takeaways

• Gunite and shotcrete are different ways to apply concrete.
• With gunite application, you use premixed dry material and shoot it through a hose to a nozzle, which is when it finally mixes with water. Gunite is cheaper and easier to clean up.
• Shotcrete application refers to wet concrete mix normally delivered by a cement truck. The shotcrete process requires less equipment and is faster.

Concrete Pool Construction Process

Whether you go with gunite or shotcrete, the construction process is essentially the same.

The process begins with measuring and excavating the ground where you want your pool. The plumbing gets installed next. From there, you install the tied steel rebar to reinforce the cage. Then it’s time to spray the concrete to encase the rebar. This is the point that you will either use gunite or shotcrete.

The next step in the construction process is to finish the pool’s shell and let the concrete cure. Once the concrete is set, you’ll install the decorative pool plaster, tile, and any other finishing materials. If you are building a patio, you will do that next. After that, all that’s left to do is apply the finish and enjoy your new pool.

Gunite Application

With a gunite application, you would load the equipment with premixed dry material. Pool builders use compressed air to shoot the dry concrete through a hose to a nozzle, which is where you add the water. The wet-mix then sprays out onto the surface of your pool at a high velocity. The nozzleman controls the application, adjusting water levels as needed to get the right mix consistency. The process makes the concrete compress as you apply it.

Shotcrete Application

Remember that shotcrete means that you’re working with a wet concrete mix. For this wet mix process, you begin with thoroughly mixed concrete. The wet concrete is delivered by a cement truck. Just like the gunite dry-mix process, shotcrete uses compressed air to shoot the concrete through a hose. The concrete sprays out at such a high speed that it bonds to itself where it is applied.

Here is one of my pool crews applying shotcrete in a pool that I designed a few years ago.

Gunite Advantages

• Gunite is cheaper than shotcrete
• With gunite, you can stop and start the application without creating any weak points
• Super high strength with low shrinkage
• You can walk on the wet concrete without disturbing it
• Gunite is easier to clean up than shotcrete
• The hose is lighter and easier to use
• Because you add water at the nozzle, the concrete is very fresh when you spray it

Gunite Disadvantages

• Gunite requires a much more experienced crew
• The hose can get clogged by the dry concrete
• Gunite can be very messy; it produces a lot of over-spray or rebound which can be tough to clean up
• The equipment requires a lot of maintenance
• Lower production rates than shotcrete

Shotcrete Advantages

• The crew doesn’t have to be as skilled because the concrete comes already mixed
• The shotcrete process is faster than gunite
• Higher production rates
• You don’t need to add water
• Requires less equipment
• In most places, it’s easy to get the materials
• It’s easier to add specialized admixtures to the concrete

Shotcrete Disadvantages

• If the hose gets clogged, it can be tough to clear, which could be dangerous for the crew and property
• You may have to add water to help with the pumping
• The hoses are very heavy and are more challenging to use for the crew
• You can’t start and stop the application, otherwise, you will create weak points in the concrete

The Bottom Line

Ultimately both gunite and shotcrete work by spraying wet cement onto the walls and floor of your pool. The difference is gunite adds water to dry concrete as you spray it. Shotcrete begins with wet concrete, so you don’t need to add any extra water.

The bottom line is that both gunite and shotcrete have advantages and disadvantages. The truth is both will produce a high-quality, watertight, durable swimming pool if you do the processes correctly. It really all comes down to what your builder prefers.

Whether you go with gunite or shotcrete, it’s important that you use qualified, trained contractors.

Hopefully, I’ve helped you better understand the difference between gunite and shotcrete today. Best of luck building your new pool!