What kind of concrete is used for pools?

Concrete is what makes up the shell of pools. However, since concrete can vary in quality and type, it’s important to know what kind you’re using. We’ve broken down what kind of concrete you should use.

The best concrete to use for pools is high-strength concrete. Concrete that is high quality has a high strength, durable and not easily eroded. The best way to tell what kind of grade the concrete you’re using is from its slump test. Slump tests measure how far a given weight will spread or slump in a given time period. If it slumps 12 inches in 60 seconds, it has a 60-second slump.

Concrete Grades

For this test, there are three grades: Type I – II – III. Type I requires a 25 minute slump, while Type III requires only a 3 inch slump for 50 minutes duration.

What you’ll use often depends on what type of pool you have built. If you want your pool to last long and you maintain your pool regularly (like what you’ll find in a public pool), what you want to use is Type II. For backyard pools, what’s more common is Type III.

Type I requires the least work but does not have the same quality as Type II or III. You can expect your pool to start showing signs of cracking after five years for this one.

Since spas are small and often tended by their owners, what tends to be used are lightweight concrete mixes which let you pour them faster. These may be cheaper than what you’d get from a concrete mixer truck because they require less concrete, only 1 cubic yard per ½” thickness instead of 2 cubic yards per inch thickness. But since it doesn’t have the strength of normal concrete mix, make sure that what you have are really what you need.

Concrete pools may require what’s called a concrete resurfacing kit. This is often used after damage has been sustained to your pool surface. It will give what is likely the most durable coat for your pool that will stand up to its harsh environment of water, chemicals and thermal conditions. You’ll find this type in many public pools since they are built with high quality concrete.

You can expect what is costlier when it comes down to what kind of concrete is used for pools. But what matters most is how long it lasts, what kind of shape it stays in, and if it contributes to the beauty of your backyard oasis or lap pool.

Find out more about concrete usage.