Bubbles in Flooring: Scenarios and Causes

Staticworx staff recently fielded a call from an installer who was encountering bubbles in a flooring installation. Here's an outline of problems and causes that might help others.

Scenario #1: No Adhesive Bond to Concrete


The bubble has been cut open to reveal that the adhesive did not bond to the concrete. Adhesive is on the back of the flooring but there is little to none on the surface of the concrete.


Contamination of the concrete or moisture may be the cause of the bubble.

  1. Check for signs that the following might have been used and not fully removed from the substrate:
    • bond breaker
    • sealer
    • curing agents
    • oil
    • paint
    • old adhesive
    • oil/wax based sweeping compounds
  2. Adhesive will not stick to a contaminated surface. Determine whether moisture is the reason for the bubble. If so, there may be a little more adhesive on the concrete and the bubble may take a little longer to develop.

Scenario #2: Adhesive Stuck to Substrate, Not Flooring


There is adhesive on the concrete and none on the flooring.


There could be three (3) possibilities:

  1. Improper rolling.
  2. The adhesive was too dry, therefore no adhesive transfer to the flooring.
  3. The back of the flooring was contaminated (dust or similar).

Scenario #3: Smoothing Compound Stuck to Flooring, Not Subfloor


The smoothing compound has released from the subfloor and is mainly bonded to the back of the flooring, including adhesive.


This is a sign of moisture, contaminants or a non-porous subfloor skimmed with smoothing compound and/or Statbond Acrylic Adhesive used "semi-wet".

Scenario #4: Adhesive Independent of Flooring or Subfloor


You find adhesive on both surfaces (subfloor and flooring installed), with adhesive squashed in the center.


This means that early traffic on the floor produced a bubble. Rolling carts, hand trucks, etc. will squash the adhesive creating a very weak bond.

Scenario #5: Bubbles Appear Days After Installation


Bubbles appeared a few days after installation, not right away.


Bubbles due to high Moisture Vapor Emission Rate (MVER), in general will show up at a later time after the installation is completed. You will find underneath that the adhesive is getting "chewy", a very dark surface on the concrete or in some cases standing water.

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