Will it, or Won't it? Moisture Sensitivity Variability of Flooring Products containing Limestone Fillers

In a project several years back, there was a "moisture-related" flooring failure that was very confusing, with no one coming up with a good answer since the same exact product was failing in a given area but not failing in other areas.

The ambient conditions were nearly identical and the moisture testing didn't reveal any significant differences.

Testing the Site Samples

There were retained samples from both areas, to which I was grateful for.

I futzed around with the samples and found no notable/visible quality issues so I decided to expose the samples to first plain water, then increasingly alkaline water.

With plain water, a difference between the samples began to be noticeable by the following day and gradually became more pronounced.

I then took sections of the different samples and exposed them to alkaline water. The difference was quite dramatic. NOTE: Having signed an NDA when conducting these tests, I have to express some of the results in very general detail.

There was a swelling effect that coincided with water absorption. It made no sense that the two seemingly identical products would have such a different reaction.

The swelling material was a limestone filler...but why such a difference in moisture response?

As I dug around....quite by accident I came across the graphic used in this article. This was an analysis of the different limestones quarried from different areas in Russia (don't ask, I have no idea how this came up in my search either).

The difference in absorption was surprising to me and it got me thinking about the differences in the absorption of the limestone used in the flooring material.

After digging around some more, there was an apparent substitution made by the limestone supplier that wasn't noted (which supported the manufacturer's claim of not going to a "cheaper" product to try and increase profitability).

When this was finally revealed, even the limestone provider was surprised; which at the end of the day, wasn't a massive difference, BUT the floor with the damage had slightly higher absorption, but there was also a notable difference in the capillarity of the "defective" limestone. The increased capillarity appeared to contribute significantly to the speed of the damage.

Conclusion - Assume NOTHING!

This was a very significant area of research directing my approach to an even more pointed root-cause analysis.

It would have been so easy and the path of least resistance to settle on an earlier "conclusion" that had plausibility, but would have ultimately been incorrect.

As I used this information to discover the difference in hygroscopicity of the various aggregates used not just as fillers, but in concrete, etc., this also contributed towards other areas of concrete research that I may not have otherwise explored.

Even as recent as last year, John T Hull, RRO, CSMT , during his ARE Roof Training class, pointed out how a rock roof can interfere with data collection using different methodologies.

The consistency in misinformation always seems to involve misidentification in one form or another.....we always need to be cognizant of the testing and data collecting process; assume nothing and verify if the data being collected is also; 1. appropriate, 2. specific enough to extrapolate meaningful information and 3. proper interpretation of such data and available information.

REMEMBER: Testing devices and methods are stupid...these identify "something".

Contrast this to a trained professional, who is tasked (and burdened) with finding out what that "something" is and what it's role is. After going through all this, I can more sympathize why doctors and lawyers call their respective businesses a "practice".