It's not fun for anyone when a strange substance starts bubbling up from beneath the floor covering.

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The story begins, as they usually do, with a phone call. The facilities maintenance director dials up the flooring contractor who installed rubber tile with a conductive, two-part epoxy in his building.

“We have adhesive oozing up between the tiles, and it’s hard to clean,” the director explains. “Can you come out and fix this?”

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Who you gonna call?

The contractor, in the company of the distributor representative, goes out to the site to inspect the problem. Upon arrival, they are given a close up look at the alleged adhesive migration (photo 1). What looks to be adhesive is coming up between the tile joints, and in some areas, the surface appears wet (photo 2).

The tile manufacturer is notified with regards to the complaint, along with the adhesive manufacturer. A second inspection is then arranged for all parties to evaluate the situation, with the facilities director in attendance.

The tile manufacturer states that the tile is well bonded to the (below grade) concrete slab, and no manufacturing defect is found in the tile.

The adhesive representative looks at the color of the oozing substance and declares that it is not his company’s adhesive, as his company’s product is black in color (photo 3).

During the ensuing conversation, someone exclaims “I’ve never seen this before,” and at least two other members of the group express their agreement.

What do you think is the cause of the adhesive oozing problem?

You Make the Call!

One of the representatives questioned whether or not moisture testing had been done before the installation, and suggested that a test be performed now. The contractor has no written documentation of any test being performed prior to the installation. The facilities director states that the building is more than six years old, so surely the slab must now be dry.

One qualifying test for moisture movement in a concrete slab is an unusually high surface pH content. The bare concrete adjacent to the tiled area was tested for pH value, and no high readings were recorded. The residue oozing at the tile joints was checked, with the results coming back with a pH of 12 (photo 4).

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Stop and think

The weakest point of every floor covering is the seam! In this case, the moisture could migrate upward and compromise the adhesive line at the tile joint, but not quite to the point of popping tiles off the concrete. Moisture migration, coupled with a high pH, caused alkaline salts to form on the surface of the tile.

Who is responsible for this condition? Who should be found liable for its repair? Can it be repaired?

You Make the Call!