Ambient Conditions - the Number One Cause of "Moisture-Related" Flooring Failures

As the narrative of moisture originating from underneath the concrete is being rapidly dispelled (finally), I wanted to give some real world examples of just how influential the ambient conditions truly are and how rapidly things can change, not just in weeks, days or hours, but even by minutes.

The Photos indicate the exact same moisture source, which exclusively originates from the ambient air. The photo on the left has so much water that would collect overnight, each time the surface was dried, the building owner was convinced there has to be some form of active water leak.

After several weeks of using expensive testing apparatus and finding no answers, the epoxy flooring manufacturer contacted me to see if I could make sense of the "leak" and its origins, particularly since several theories were being discussed and they were losing valuable time in not being able to coat the floor and button up the project.

As soon as I arrived, I felt I knew what the problem was, so I took out an infrared thermometer and measured the overall concrete floor surface temperature, which was averaging 72oF. As I brought the infrared thermometer beam closer to the metal wall (which turned out to be an inadequately insulated refrigerator), the concrete surface temperature was 55oF.

I informed them that the concrete surface temperature was below dew point, which explained the large accumulation of water overnight.

My advise to resolve the problem was to have them cut directly against the metal wall, at least 0.75 inch depth, understanding that the gradient portion of this type of concrete was likely limited to the top 0.75, and had them place an insulating caulking material.

The concrete surface temperature gradually warmed up over the course of a few hours and after two mornings in a row where no additional water was noted in this area, they were able to proceed, with no further moisture issues.

Professional Basketball Game Cancellation due to Damp Floors that Wouldn't stay Dry

In a web search, I think most people would be shocked to see how often this happens where a wooden parquet floor becomes damp immediately before a game, necessitating postponement of the game due to dangerously slippery conditions.

This particular game was the Miami Heat vs The Philadelphia 76ers (corrected to Trailblazers vs. Timberwolves) - thanks Jonathan Porter, PE, Assoc. AIA .

The issue was that auditorium hadn't sufficiently been cooled prior to the game.

Underneath the parquet floor is a hockey rink, which under normal circumstances isn't an issue since the auditorium is usually chilled for several hours, with a robust humidity control.

In this situation, because the ambient conditions were not controlled properly, as more and more people showed up, the humidity within the auditorium began to climb, creating a dew point issue on the much colder floor surface.

Fans, mops, etc. were brought out and no sooner would an area become dried, once the fans were moved to another area, the previously dried surface would again become dangerously damp, with the players slipping and sliding over the floor, causing very hazardous conditions for these multi million dollar athletes.

They had no choice but to cancel the game for that day.

Job Sites: Usually less obvious, but no less dangerous

In job site conditions, the flooring contractor usually has little to no influence in what is needed to optimize the ambient conditions.

Open doors, windows, respiration of workers, moisture laden job site materials, etc. can come into play, particularly with materials being brought in from outside and not sufficiently acclimated.

As an aside: One project where the floor had failed due to moisture twice and was being prepared for reinstall for the third time, the job site inspector called me, asking for advice.

After discussing the site details, materials being used, etc. I asked if the flooring materials had been acclimated. After I was assured the materials had been acclimated, I asked how long had they been acclimated.

The flooring materials had been acclimated and I had the inspector use an infrared thermometer on the hard goods, which were all at room temperature.

COMPLETELY overlooked however was the liquid adhesive. When the temperature of the adhesive was taken, it was well within dew point. I informed the inspector that liquid materials (especially in larger containers can take well over a week to acclimate and by using an adhesive that was significantly colder than either the ambient air temperature as well as the concrete temperature, moisture tends to move from warm to cool, so the cold adhesive would attract moisture from the room AND concrete..hence the adhesive was acting as a "bond-breaker sandwich".

Sure enough, when the adhesive was warmed to room temperature, the installation was without incident.

There are so many details missed before and during installation that the majority of issues are introduced in these critical blocks of time; which is why Time of Installation testing is THE most critical measurements that can be taken.

Even if moisture tests were concluded the day before an installation (which rarely happens, normally it can be weeks before the testing ends and the installation begins), the initial tests can now be rendered useless and even misleading for the current conditions at time of install!

22nd Floor and 3rd Floor Moisture-related Failures

A very respected Inspector, prominent in virtually every flooring organization I can think of, experienced a condition where the 22nd floor had a higher moisture level than the on-grade concrete. This was a pretty good example of the soil being a contributor, much less as often cited, the main cause of flooring failures.

On another project, in a three story building, the third floor has the highest moisture average, higher than the second floor and the second floor has moisture levels higher than the on-grade floor.

The three story building was an unconditioned space and a great example of the stack effect caused by warm air rising that will "hold" more moisture and then cyclically continued to add moisture to the upper two floors....with what SHOULD have been predictable the third floor had the highest moisture readings...again, 100% of the moisture contribution was due to ambient moisture, NOT moisture originating from the concrete itself.

The 40 Year Old Warehouse

Just last year, I was surprised yet again, just how quickly site conditions can alter the suitability or potential success of a flooring installation.

In a class being given to a large installers group at their training facility in Northern California, I was asked about older concrete and why older concrete seems to be more problematic than newer concrete, even though the older concrete was typically drier.

I informed them that concrete is NOT inert and that it undergoes constant changes as it ages. Older concrete tends to accumulate salts towards the surface, yet these salts remain somewhat innocuous since there is no "active moisture source". NOTE: Salts tend to become more active and soluble with increased temperatures as the moisture wants to migrate towards a cooler interior area of the concrete, leading to something of an impasse between the saltier gradient concrete surface and the cleaner and cooler moisture within the concrete. This puts the surface into something of a dynamic equilibrium where neither the salt nor moisture move nearly as much, if at all when the concrete was newer.

NOTE: Recent studies have concluded that it isn't unusual for concrete to become adiabatic (where temperatures neither increase nor decrease within the concrete) and that concrete, as it ages develops hysteresis, which produces concrete with a greater capacity to absorb moisture rather than desorb moisture....this information is another area NOT taught in certification schools. Teach em to test, not the ability to interpret.

The installers had never heard this information and were a bit skeptical, until not three months later the same group was learning how to use an Electrical Impedance Meter.

The warehouse concrete had been in place for slightly over 40 years. The meter reading were taken over the existing surface, and not surprisingly, the moisture levels were extremely low at 1.9%.

The surface was ground down to expose an absorptive concrete surface and retested. The readings remained at 1.9%.

The group went over to a different area and returned what was estimated to be only 10-15 minutes later. When the impedance meter was placed on this same area, the moisture levels increased dramatically to 4.3%!

It MUST be emphasized that the meter averages out the moisture content over a 0.75 depth of the concrete, meaning there is a LOT of moisture being absorbed into that surface, VERY quickly!

Right after this result, they gave me a call from the job site, and to be blunt, the speed in which the concrete surface absorbed moisture from the ambient air really surprised me.

Surface Moisture Testing and Depth Testing

Recently an inspector out of New England has tested both the surface and in depth testing using Electrical Impedance. BOTH projects were of 40 and 50 year old concrete.

The top surface had excess moisture in the 6-6.8% range, while the depth testing had much lower moisture test percentages ranging from 2.1-3.0%.

After grinding the surface, as the grinding got deeper, there was a reciprocal reduction of moisture percentage, once again, showing the effects of salt accumulation over several decades, and that the moisture was NOT originating from the concrete itself, but absorbed from the air after the existing flooring material had been removed, giving the salts a "new" moisture source.

Solving these mysterious problems has really increased the perception and reputation of this inspector.

The Explanation and what we are REALLY Faced With

When salts accumulate in a concrete surface, in warehouses this can and DOES cause a concrete slab surface to become physically dampened. This is called "Sweating Slab Syndrome".

In a less severe environment, this moisture WILL accumulate, but not where it is visually observable.

NOTE: Just think of this as an upside down calcium chloride dome kit but this time instead of the moisture being absorbed from the concrete into the airspace beneath the cover, it is the moisture being absorbed from the air into the concrete!

If these initial tests hadn't been taken, before after and then again at a slightly later time period, the ASSUMPTION would have been this moisture is originating from the concrete, or that the MC values must have been "faulty".

I say repeatedly that none of these devices or techniques are necessarily faulty or defective...only our interpretation of the data.

Empirical Data - If it Doesn't Exist. It Ain't a Fact!

I have been asking for nearly 3 decades for ANY facts regarding what I and so many others were taught and told as fact that moisture migrates from the underside of concrete to the surface and THAT is the main cause of moisture-related flooring failures.

I STILL have yet to receive any empirical data, and even without data, there are those that fight tooth and claw insisting this is factual, even when they haven't produced a single bit of tangible proof of this phenomena.

Moisture Migration - A Case of Mistaken Identity

Some of the "suggested" proof is when a contaminant from the underside eventually makes its way to the surface as "proof" of moisture migration.

That suggestion is a case of mistaken identity. When this happens and it typically takes decades to manifest, this is actually an example of diffusion.

If a soluble contaminant enters an area of a purer solution, the contaminant will, through diffusion, attempt to equalize throughout the available solution.

The solution acts as a transport medium even as the solution itself remains in a static (non-moving) condition.

There are different dynamics that can cause moisture and contaminants to move and knowing the difference is critical in attempting to identify then SOLVE the problem.

Dumb and Junk Science

Some of the theories forwarded are the reason the flooring industry has been beset by so many ridiculous causalities and garbage/junk science. If it sounds impressive, then by golly, it must be true.

Hydrostatic pressure flooring failures, along with vapor pressure failures are two prime examples of dumb and junk science.

Hydrostatic pressure exists due to the downward pressure of gravity. the Pressure is wholly dependent upon the depth of the water. THAT is dumb science....vapor pressure is junk science.

Vapor pressure in floors does exist, but at such low levels that the pressures cannot be measured, only calculated, or as my favorite analogy from Dr. Joe Lstiburek; "about half a gnat fart".

Some of the junk science "supporting" these tremendous vapor pressures happens when someone pokes a hole in a floor and the water comes up very impressively, resembling a geyser....that is a "dog and pony show".

That is an example of restrained pressure, where the impressive leakage slows down and seemingly stops. It stops because the only pressure was the restraint of the floor pressing down on the fluid, once the pressure is removed, no more geyser or obvious water flow.

The Needle is Moving

There are some groups that have experts from a variety of the disciplines and building sciences that have banded together to proper educate and most importantly re-educate the flooring industry.

There are no justifiable reasons that the now 3 billion dollar per year moisture-related failures should even be a discussion point, much less the industry it has become for those who benefit from avoidable failures.

There is plenty of pushback, even as these pushback arguments are bereft of any tangible fact. If there is a perception that any effort threatens their business, does ANYONE think those who feel threatened, will in any way support this direction?

Ironically, this direction will probably increase the need for professional inspections. My push to this direction is what prompted my authoring of the 2001 White Paper Flooring Industry Position on Moisture Testing.

Unfortunately, many who had zero input into this document, tended to misuse its intent and brought us back around to junk science and even more unfounded causalities.