The Three Types of Inground Swimming Pools
When it comes to building pools, there are three basic types of inground swimming pools: fiberglass, vinyl, and gunite.
Gunite Swimming Pools (aka concrete or dry-mix shotcrete)
Don’t let those different names like “gunite” and “concrete” confuse you. They’re all the same thing. All we’re talking about here is a special type of concrete. The reason it has a fancy name is because it’s a little different than the concrete you’re used to seeing being poured for sidewalks and buildings. Basically, all the dry parts of gunite concrete are mixed together in a factory, and brought on site in a dry form, rather than in a big mixing truck with a constantly rotating drum that you see at construction sites. The dry gunite is blown through a large hose at very high pressures. When the gunite mix goes through the nozzle of the hose, right before it hits the air, water is injected into it, and this final mix is what hits the surface of what will become your swimming pool. This special process allows swimming pool contractors to do things with concrete that would otherwise be impossible: curves, slopes, and vertical walls.
Because of the flexibility of its application, the possible shapes, sizes and designs are almost limitless. This alone may be why gunite inground swimming pools are the most popular type of swimming pool in the country. If you’ve ever seen a pool that was so beautiful it made your jaw drop, then it was probably a gunite pool. A small desert oasis, a world-class Olympic diving pool, or a jungle paradise: they’re all possible with gunite.
Fiberglass Swimming Pools
Fiberglass is a type of rigid, reinforced plastic that is used in a massive number of applications: cars, planes, boats, water tanks, pipes, surfboards, and of course, fiberglass inground swimming pools. Fiberglass swimming pools are pretty unique in that they are pre-made as a single, molded piece in a factory setting, and then trucked in to where a pool is being built. They are the most limited type of pool when it comes to shapes and designs, because they are made from a preexisting mold. Essentially, you look at a catalog of pool models and choose the shape and color that you like, sort of like different models of cars or trucks. The great thing about this is that you have a very good idea of what the finished product will look like: what you see is what you get.
Fiberglass pools are basically plastic, so their surfaces are smooth, making them gentle on hands and feet. The flexibility of fiberglass makes it particularly cold-tolerant, so fiberglass inground pools are particularly common in the Midwest and Eastern United States. Fiberglass is nonporous—meaning there aren’t tiny little holes and spaces in the surface (imagine a piece of bread)—so algae has a tough time holding on. This cuts down a lot on the number of chemicals you have to use to keep your pool looking bright and brand new. They are perhaps the most durable type of inground pool, requiring the least amount of repairs in the long run.
Vinyl Swimming Pools
Yep, the stuff they use to make records (they still make those, right?) can be used to make swimming pools as well. Vinyl is a great material for a few reasons. It’s cheap, perhaps the cheapest type of pool to install, with some of the advantages of both fiberglass and gunite. Like fiberglass, the material is nonporous, so algae is easy to clean up, but you can also have any shape or size of swimming pool, as is the case with gunite.
The concern with vinyl is that it is the most fragile of the three types. A vinyl liner is about three-quarters of an inch to a little over an inch (3/4” to 1+” thick). So you really have to be careful when it comes to tree limbs, dogs, rambunctious dogs, spear guns… You have to be gentle with a vinyl inground swimming pool, and the liner will have to be replaced within about 7 to 15 years. Don’t get us wrong, vinyl swimming pools can be great, but if there’s a lot going on in your home, then you’ll want to take a look at gunite or fiberglass.