If you’re a professional contractor that specializes in the installation of epoxy floor coatings, then you know the importance of concrete preparation. This step is critical to installing high quality floor coatings. An improperly prepared concrete floor will cause issues over time even if you’ve used the highest-grade coating products around!
Concrete Surface Profile
It’s all about concrete surface profile (CSP). For coating products to properly bond, the concrete needs to be textured. Simply stated, it needs to be rough because smooth concrete doesn’t provide a receptive substrate. According to the International Concrete Repair Institute, the roughness of concrete surfaces can be ranked. A smooth surface will have a “CSP” ranking of 1, while the roughest surfaces, a CSP of 10.
There are many methods that can be used to prepare concrete, from low-pressure water jetting and acid etching to more aggressive sand blasting and rotomilling. Because low pressure water jetting and acid etching produce too low a CSP (<2), they are simply not good enough for long-term bonding of a newly applied epoxy coating. This leads to peeling, especially in high-traffic areas like garage floors. Conversely, sand blasting and rotomilling produce high CSPs (>4) which are unnecessary for the purpose of epoxy paint application in most residential areas.
The Sweet Spot
Grinders can produce CSPs of 3 and up to 4 in some cases, which, when prepping concrete for epoxy coating applications, is in the Goldilocks range.
However, the type of grinder selected is as important as the mode of concrete preparation. Although electric grinders are a lot cheaper to buy than propane grinders, they are less powerful. Equally important, electric grinders take much longer to grind an equivalent space than their propane counterpart. This translates into extra man-hours and higher labor costs. Propane grinders may be expensive at the outset, but the return-on-investment occurs quickly.
This is yet another reason why DIY application of epoxy coatings is never a great idea. The equipment required to properly prep a concrete floor can be prohibitive for DIYers or contractors that do not specialize in epoxy coatings applications.
Are Propane Grinders Safe?
Propane grinders are safe and are especially important for use in commercial flooring environments. Don’t try to grind large commercial spaces with an electric grinder…you’ll regret it. Propane grinders do not require electricity and so they move freely through the work space without the worries of electrical extension cords, especially in spaces that tend to be wet or damp. For those that worry about the flammability of propane, know that it has a very narrow and very high temp range of flammability (unlike the gasoline in your car!). And because a propane grinder produces a near zero exhaust emission, it may even be used indoors.
Ensure you (or your hired contractor) are using a grinder (preferably propane) to prepare the concrete. Any other method that produces CSPs outside the “Goldilocks range” may bring you unneeded headaches in the form of repairs. So the message here is to hire an epoxy floor specialist who knows the importance of concrete preparation. His or her use of a professional grinder is a sign you’ve chosen the right installer.
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