So if the traditional, cementitious terrazzo is great for basements and the outdoors, and polyacrylate terrazzo allows a wide variety of colors, why is there a third option? In the past, traditional was the only choice. Then epoxy, or resin-based, terrazzo came along in the 1970s and revolutionized the world of terrazzo flooring, making it much more affordable. According to the National Terrazzo & Mosaic Association, epoxy has more 70 percent of the terrazzo market. It's the most versatile, the strongest and the least susceptible to scratching, fading, cracking or staining.
You can have epoxy terrazzo flooring that's just a quarter of an inch thick, and it can go over a prepared concrete slab or even on top of plywood sub-flooring depending on the thickness. It's installed in multi-story buildings because it's so light -- about three or four pounds of weight per square foot. Epoxy terrazzo is available in any color and is the best for making intricate, multi-colored designs. You can install it with very few dividers, especially if it's being installed over plywood. It also can't be penetrated by moisture, so epoxy can't grow mold, mildew or bacteria.
That non-breathable quality is great for sanitary purposes, but it also means that moisture can get trapped between the concrete slab and the terrazzo topping. Some contractors will install a vapor barrier between them to help with this problem, which can lead to the topping becoming loose. It also can't be installed outdoors -- one, because it's non-breathable, and two, because the epoxy can fade with exposure to sunlight. Another downside is the solvent used in installation and cleanup with some types of epoxy terrazzo. There are some solvent-free versions, and only those kinds can be used in places with common ventilation systems like hospitals. Otherwise the fumes are too strong.
As you can see, each type of terrazzo has its pros and cons, depending on what you want. They're all going to be more expensive than many other types of flooring. We'll look at intensive process of installing terrazzo next.