First off, you have to understand that these two pool deck products are not inherently the same thing. One is to improve visual design, by making plain concrete more appealing, and the other is to improve usability, by making concrete heat resistant and therefore safer for bare feet that are just itching to jump into the water. Let’s look at both. Sundek was started in 1970 and is a concrete overlay that can be stained, painted, and carved into just about any design you can imagine. If you’re looking for a dark brown cobble stone appearance, Sundek can do that. If you’re looking for a light pink flagstone design, Sundek can do that too. And having a Sundek overlay installed by one of our friendly experts is cheaper than attempting to install the individual stones or bricks that would be needed to replicate the look. Kool Deck (many misspell it as Cool Deck) was invented all the way back in 1962 and, while it can be colored anything from Aztec Gold to Birch Grey, the most valuable aspect of Kool Deck is the thermal resistant coating that is put on top of the concrete. It actually lowers the surface temperature of the concrete, making your pool deck a safe environment in the sweltering summers. This is a fairly affordable and aesthetically pleasing way to make your pool a cool deck pool.