What Those Bubbles In Your Epoxy Floor Mean

Bubbles in an epoxy floor mean air is escaping from the concrete beneath the coating during curing.

Small, perfectly round circles have popped up on the surface of your freshly applied epoxy coat. Fear not, as this issue is actually a very common byproduct of an effect called “outgassing.”

And while this surface anomaly may take away from your floor’s aesthetics at first, it does not affect the integrity of the coating itself.

Outgassing occurs when trapped air or gases inside the concrete are released. This condition is temporary and typically happens during installation, unlike the more serious issue of moisture vapor transmission (MVT), as we’ve covered in a previous blog series.

Outgassing produces two distinctive faults: small blisters, referred to as “pinholes,” which leave a small, round crater in the coating after popping or the release of gas.

The other is bubbles that emerge out of the coating.

What's the Difference Between Outgassing and Moisture Vapor Transmission?

As an epoxy floor sets and outgassing occurs, bubbles rise to the surface and can trap liquids and dirt.

Bubbling can also happen if the concrete itself has air trapped inside. When pouring an epoxy floor, the air might then escape from the concrete and cause bubbles on the surface. The outgassing can occur from changes in conditions in the space, as well.

There are several methods professionals employ in removing bubbles from epoxy floors. They include:

• Roll it out. Spike rollers can remove bubbles quickly in the epoxy floor.
  
  
• Reprime time. If bubbles rise after the installation due to outgassing of the concrete, then it may require a reprime of the affected area. This ensures the integrity of the floor when applying future coats.
  
  
• Sand it down. If bubbles are present following several additional coats, an installer may choose to sand down the affected area, followed by patching the area prior to applying a topcoat.
  
  
• Give it some heat. For a few scattered bubbles, a simple heat gun can easily break up bubbles.

It’s important to remember that while epoxy bubbles and craters may be an unattractive sight, they do not affect the bond strength of the coating. And while installers have a few tricks up their sleeves to tame outgassing bubbles, always seek out professionals who take the time to conduct proper preparation and avoid issues from the beginning of an installation.

What do bubbles in an epoxy floor mean?

They indicate air escaping from concrete beneath the coating during curing (outgassing).

How can bubbles in epoxy be prevented?

Proper preparation during priming or patching epoxy floors is key to a successful installation. Some things to keep in mind: concrete slabs outgas when they warm up. Depending on conditions, waiting until the slab is cool can help prevent bubbles. Also, since air can be introduced into the material during mixing, spike rolling may be necessary to prevent bubbles in the application. Some formulations include air-release additives to prevent this issue. 

Can bubbles in epoxy flooring be fixed?

Yes, surface bubbles can usually be corrected through sanding, recoating, or other professional remediation methods.

Stonhard is the unprecedented world leader in manufacturing and installing high-performance polymer floor, wall and lining systems. Stonhard maintains 300 territory managers and 200 application teams worldwide who will work with you on design specification, project management, final walk-through and service after the sale. Stonhard’s single-source warranty covers both products and installation. Contact us to learn more about our precision installation methods and specialized products.