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Prevention from Outgassing in High Heat

July 16, 2020

Outgassing is a phenomenon in which the volume of air in concrete increases with rising temperatures, and forces the entrained air in the concrete to escape. Air pushing through a primer, sealer, or self-priming body coat during the initial cure will result in outgassing bubbles in the setting resins. Outgassing bubbles can have varying appearances depending on the product composition, coating thickness, and stage of cure at the time of outgassing. So how can contractors limit their exposure to outgassing when installing coatings in high heat?

  • For Dur-A-Flex Epoxy or MMA coatings, do NOT install when slab temperatures exceed 90°F; when installing Accelera or Dur-A-Flex cementitious urethanes, do NOT install when slab temperatures exceed 85°F
  • Apply coatings when the substrate temperature is warmest and the slab temperature will be decreasing.
  • Monitor and control any potential sources of heat.
    • Take steps to limit the exposure of direct sunlight on the concrete by setting up a tent/barricade, or installing once the sun has passed over the application area.
    • Block indirect sunlight from warming the airspace of an un-insulated building or garage.
    • Avoid space heaters that cycle on and off.

For more on ongassing, see Tech Notes “Outgassing”.

Please contact the Dur-A-Flex Technical Team with any questions or concerns.

Bret LePard
Technical Services Manager – Midwest Region


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