The gunite versus shotcrete debate has gone on for 80 years, and both processes have many benefits and detriments. Ultimately, deciding which method to use when installing your home pool comes down to several variable factors. PoolsandSpaNews.com looks to settle the debate once and for all by bringing in the experts to layout the facts of the pros and cons for each method of swimming pool installation. Determining whether to use a wet or dry mix method is based on the application process available to the project and the preferences of the pool builder. The disadvantages of gunite are that it is more expensive than shotcrete, and the wet mix must be mixed on site, and if not done properly can lower the quality of the gunite mix. Gunite has developed a bad reputation over the last 30 years due to its improper use in the home pool industry leading to failed projects.
It is common for workers using gunite to lower the quality by adding too much cheap sand and water to the concrete mix. However, under proper supervision, mixing gunite on site can be beneficial to the builders who can see the mix as its being created, and adjust the mix as needed. This has given shotcrete a reputation of overall being more reliable because the batch plants that produce it can verify the strength of the concrete. Advantages of shotcrete are that it is cheaper and more consistent because it can be made in large batches at plants and delivered on time to project sites in more developed areas of the country. Although shotcrete is less expensive, it is more prone to breaking down earlier in its life cycle. Whereas gunite is more expensive upfront, costing on average $72 per square foot, but is more durable and cost effective in the long run. Gunite is better than shotcrete at doing detail and precision work in pools with features such as vanishing edges and perimeter overflow due to the perfectly flat surface required to facilitate flow because of the nozzle used to cut flat surfaces with no texture. The reputation of each process varies based on region due to accessibility of the materials, and success of the process in each region. For example in Pennsylvania, the birthplace of gunite, almost every pool contractor uses a dry mix gunite process for constructing swimming pools.
Reports from the Lehigh Valley indicate that there are far less serious malfunctions when switching from shotcrete to gunite. On the other hand shotcrete is much more common on the west coast, and reports from California claim that gunite has more problems than shotcrete. Although the two processes are very different and the professional community is divided over which method is best, both gunite and shotcrete can be used to achieve similar results. Overall each method has its own advantages and disadvantages and deciding which to use is determined by several variable factors such as budget, builder preference, time frame, pool style, and region.