What are Gunite and Shotcrete?

Are you currently in the process of trying to create the perfect concrete pool for your home? There are so many options on the market nowadays, and it can be difficult to decide what material to choose. You might have heard some unfamiliar terms being thrown around, such as gunite and shotcrete. While they are forms of concrete, we can help to break it down a little more, so that you get a better understanding of what is what, and which one might be the right choice for you. 

Gunite and shotcrete are both different types of concrete. They are both comprised of the exact same materials – sand, cement, aggregate, and water. What differentiates gunite and shotcrete is simply the point at which water is added to the dry materials to turn it into the concrete. Gunite is known as a dry mix, because the water is added very late in the procedure, and shotcrete is also known as a wet mix because water can be added in much sooner. Both of them can be used to create long-lasting concrete pools, as well as a range of other applications. They both share a number of benefits compared to regular poured concrete, including less shrinkage, lower costs, and better adherence to surfaces.

What is gunite?

Gunite refers to the material that is made when water is added to dry concrete at the very last second, through a gun-shaped nozzle that then gets sprayed onto the waiting pool structure (hence the name gunite). This is known as dry-mixing, as the concrete is only mixed when it is ready to be used. 

Pros of using gunite

Gunite is a lot cheaper to use than shotcrete, making it a great choice for those wanting to save money (especially on bigger pools). When it is completely dry and fully cured, it is a much harder material, and much less prone to shrinking and cracking. As it is prepared on-site (literally as you use it), constructors have a much larger window of opportunity to get everything done accurately and evenly, so there are less likely to be errors in the way that it ends up. Gunite is a lot stronger than shotcrete and has a compressive strength of up to 9,500 psi (shotcrete only has a compressive strength of up to 7,500 psi).

Cons to using gunite

Gunite is not perfect, and there are a number of cons that people should consider before using it to build their pool. Contractors need to manually mix in the water with the dry materials, and this creates the opportunity for user error. If you have chosen a contractor that has years of experience with gunite and knows exactly what they’re doing then this shouldn’t be a problem, but it is still a possibility you need to consider. Because of the way that the concrete is mixed in the nozzle as it comes out, you have a much higher risk of rebound or overspray. These terms simply refer to excess concrete that has spilled, resulting in larger amounts of waste, and more cleaning to do at the end. 

What is shotcrete?

Unlike gunite, which is made on the spot when you need it, shotcrete powder is mixed with water beforehand, this is referred to as wet-mixing. It will arrive at your house (or wherever your pool is being built) as wet concrete. It is then shot out of a hose (hence the name) at your pool structure, creating the concrete sides and bottom. There is no need to spend time mixing the concrete together, it can be used immediately. This is the most common form of creating concrete pools. 

Pros of using shotcrete

Shotcrete was traditionally used to create concrete pools, and it is evident as to why – there are a number of benefits to this method. It is much faster to apply, it is durable, and it is much easier to create an even layer of concrete with no weak spots. Premixing the concrete helps to ensure that ratios are all correct, and you can be certain it will create a coating of the right consistency. With the shotcrete method, there tends to be less wasted rebound material, resulting in a neater finished product that doesn’t require as much unnecessary clean up afterward. 

Cons of using shotcrete

Of course, shotcrete isn’t perfect, and also suffers from its own drawbacks. Because it is premixed you often have less time to apply it, and hasty application is more likely to lead to issues if your contractor is not experienced enough. If you do find yourself running short on time you can add more water to stop it drying out before it is ready, but this will potentially weaken the final concrete structure. Although the risks are low, shotcrete does have a higher chance of shrinking and cracking in comparison to gunite, which can compromise the integrity of your pool. Shotcrete tends to be more expensive than gunite, which can be an issue for those on a tight budget. 

Gunite vs. shotcrete – which one is better?

Both of these choices come with their own pros and cons, neither one of them is going to be better than the other in every situation. If you have done your research, you may be able to tell which option will work best for your pool needs, or you may find that both will work equally well for your situation. Remember that regardless of what option you choose, as long as you hire great contractors your end result should be a great, long-lasting pool.

Make your choice based on local professionals

Perhaps one of the best ways to decide if gunite or shotcrete is right for you is to shop around local professionals. If you live in a large enough town or city, chances are you will be able to find highly experienced contractors who can perform both methods to a really high standard. But if you live in a smaller area, you might just be limited to what local contractors can provide you.

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