Here’s a prime example of why an epoxy floor system needs a fully tinted top coat. What you’re looking at is an epoxy novolac top coat. And those dark spots are the intermediate coat poking through the top coat.
Epoxy floors are most beneficial when they have multiple layers of epoxy. Base coats allow for outgassing, intermediate coats add some beef to the system, and the top coat is usually the performance coat.
And as long as each epoxy coat is compatible and installed within the recoat window, you could expect exceptional adhesion between all the coats.
But the one overlooked feature of these floors is the color. And if your color between the intermediate and the top coat aren’t lining up, then you could have a spotty, unprofessional floor.
So Here’s What You Need To Look For:
Ideally, the intermediate coat, and the top coat need to be the same tint. And if they aren’t the same tint, the top coat needs to be darker than the intermediate coat.
But in the sample posted above, the intermediate coat is on the left, and the top coat is on the right. The intermediate coat, is clearly the darker tinted floor. And as you can see through the top coat, the darker intermediate coat is poking through the top coat.
So, the first fault in this sample is that the top coat should either be as dark as the intermediate coat. Or the intermediate coat should be lighter, to match the top coat. If the intermediate coat was a lighter color, you wouldn’t see the intermediate coat poking through the top coat.
But, another potential issue to be aware of is how much tint the top coat has. This is always a tricky area. Because you want as much tint as you can get, so that the epoxy material has great coverage and hide. However, the more tint you put into the material, the more you are jeopardizing the integrity and the mix ratio of the epoxy. So from the manufacturer’s perspective, this is a delicate situation.
And it becomes very delicate when dealing with specialty epoxies like novolacs. If you read the difference between the epoxies, then you’ll see that some epoxies aren’t as temperamental, and can handle more tint than others. But novolacs can’t handle the tint, nor should you want them to. The largest benefit of the novolacs is that they have excellent chemical resistance. But if you dump in too much tint, then the benefit of the novolac diminishes with each additional ounce of tint.
So in the example above, a fully tinted standard 100% solid epoxy may have covered the dark intermediate coat. However, because the top coat was a specialty coating, it couldn’t take on any more tint, without compromising the purpose of the novolac.
So when in the field, installing a performance floor for a commercial or industrial customer, be sure that your flooring system is involved similar tints in each epoxy layer. Or you may end up returning to the customer’s job site to install free work.