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How to Waterproof a Concrete Pool

Alpha West reps using Basecrete to waterproof a concrete pool

As anyone who’s ever gone over the handlebars of their bike knows, concrete is tough. And that’s why it’s such a popular choice for those who seek an ultra-durable, long-lasting swimming pool. But most don’t expect that something so resilient also has its weaknesses. However, everything has its weaknesses. With concrete, that deficiency comes in the form of being porous.

Concrete Is Not Invincible

Yes, while that sturdy concrete pool will stand up to all kinds of regular wear and tear from play dates with the neighborhood kids or years of raucous pool parties, unassuming looking water can still penetrate its walls. This is where mighty concrete needs a little backup. 

Efflorescence and How to Avoid It

efflorescence on a pool
All concrete swimming pools need to be waterproofed to prevent efflorescence.

When improperly applied concrete is left exposed to water, efflorescence occurs. The term refers to soluble mineral salt deposits that are left behind when water seeps through concrete and then evaporates. This is not to be confused with calcium/lime deposits, which can also occur when water moves through concrete. Calcium/lime deposits appear less powdery and surface level, and are usually more streaky and embedded. 

With efflorescence, there are two types to be aware of—primary and secondary. When water pulls minerals to the surface during concrete’s curing time, this is known as primary efflorescence. Secondary efflorescence happens when water moves through already cured concrete. Basecrete protects against both types of efflorescence.

Why defend against efflorescence? Over time, salt deposits damage concrete. While it’s always best to avoid efflorescence altogether by waterproofing concrete pools before exposing them to water, some waterproofing can be done to repair existing issues. To repair water-damaged concrete pools, waterproofing product, Basecrete, can be rolled on to fill in damaged areas and prevent erosion.   

Concrete Pool Exceptions

If concrete is applied at a high enough density and applied well, and the entire pool shell is in-ground, then the pool may not require waterproofing. That said, in almost all cases, waterproofing is recommended. Both shotcrete (pre-mixed concrete that is applied through a hose) and gunite (concrete powder that is mixed with water inside the application equipment), greatly benefit from waterproofing. It’s important to remember that, no matter how well built your concrete pool is, the cost to waterproof a concrete pool during the building stage is far less than the cost to repair a concrete pool with water damage.

And if concrete is not applied at the appropriate density or there are raised portions of the pool, such as pools that are built with a vanishing edge or in-ground spa, then that concrete needs extra protection. It’s also vital to take into consideration the water behind the pool shell. If you live in an area with a high water table, protecting the entire pool surface is absolutely the best course of action. 

Waterproofing Concrete

The process of waterproofing a concrete pool is quite straightforward. Using Basecrete, which is an all-in-one waterproofing product, made from a mix of polymers and specialized materials, it takes only a few basic steps and a bit of patience to allow for cure time.

Before starting it’s important to keep in mind that steps, corners, and benches are the most vulnerable areas, so they require careful attention in the application process. Before getting started, you also want to be sure that you are starting with a clean, dry surface.

professional pool builder mixes basecrete to waterproof concrete pool
A professional pool builder mixes Basecrete to waterproof a pool.

Begin by mixing the appropriate amounts of Basecrete powder to the liquid from the kit. Each kit consists of three 50 pound bags of powder compound and one 5 gallon bottle of liquid. You should get a mixture that has a pancake batter consistency. Keep in mind that if your mixture is too thick, you must use the liquid from your kit to thin it. Adding water ruins the integrity of the product. That said, using water immediately to clean Basecrete from other surfaces is ideal.

a team of pool builders waterproofing a pool
A team of professional pool builders waterproofing a concrete pool.

Next, though you’re starting with a dry surface, you need to add a small amount of water to the surface to give the product something to grab onto. The mixture can then be smoothed on with a brush, trowel or squeegee. Once the first layer is applied, it needs to cure. We do recommend a 24 hour cure time.

Apply the second layer of Basecrete with an 1-inch nap roller. Allow the second layer to cure the same way as you did with the first. Once it’s dry, the waterproofing is complete and the surface is ready for the final pool surfacing product. While the second layer of Basescrete can be applied smoothly (like the first coat) if it’s being used as a finish, the nap roller creates the perfect slightly textured base for gripping tile or other finishing surfaces. 

Because Basecrete effectively blocks water from moving through the concrete pool shell, tiles stay properly affixed to the surface, as there is no moisture or efflorescence to disrupt the bond. In floated areas, ⅛ inch of Basecrete, applied with a trowel, is recommended. A ¾ inch nap roller or brush is ideal for applying Basecrete before plaster to achieve the perfect grip for a mechanical bond. Mortar holds fast to Basecrete on the tile line, negative edge, and top of the bond beam, so the added thickness is not required.

Cured Basecrete is a fantastic surface for glass tiles such as the high-quality and eye-catching options available from Artistry in Mosaics. These stunning tiles are available in a wide range of colors and styles. There are even hand-painted, custom mosaic options available for those who want something truly one-of-a-kind.

glass tile spa in a pool

Pairing top-quality products such as Basecrete and Artistry in Mosaics tiles protects the client’s investment. If you want to learn more about waterproofing a concrete pool, reach out to us.