Tech Tip #2: Applying Sealers over MicroTop and Thin Coat Warning

IMPORTANT: MicroTop or Thin Coat Concrete Overlay Product Reaction to Sealer Warning!

When sealing heavier polymer modified thin overlays and micro-toppings, you must use caution because using the wrong type of sealer, sealing at the wrong time, or not sealing the product properly, could have disastrous results.

Most concrete and polymer based Micro-Toppings and Thin Coats have a heavier polymer load and less concrete which is what allows them to be applied at a thinner viscosity and still reach full concrete hardness once cured.

However, the heavier Polymer Loaded concrete overlay when applied thin…also reacts differently than other concrete overlays, especially when using “solvent-based” sealers and applying the sealer before the concrete has a chance to cure properly.

If solvent based sealers are applied too soon, it could cause your overlay product to:

  • Re-emulsify the surface and cause a look we call elephant skin or orange peel.
  • Shrink and crack, where the crack edges curl up because of the shrinkage
  • Delaminate off the substrate in sections or in sheets

Solutions & Options

Use a Water Based Sealer: When applying thin overlays or micro-toppings, apply a “heavier solids”, water-based sealer with two thin coats. A 30% solids or more water-based sealer would still make the colors “pop” and not have any of the solvent or xylene that could harm the surface if applied too soon.

Wait 3 – 7 days before applying a solvent based sealer: If a solvent based sealer is desired, wait 3-7 days to allow the overlay or micro-topping sufficient time to cure, alleviating any additional shrinkage to the product surface and allowing the solvent-based sealer to penetrate the surface without harm.

These are just a few helpful tips to allow you to have even greater success when applying sealants to thin overlays. Happy Overlaying!

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