Now with that said, they didn’t ask me if these moisture tests were reliable or not. The answer to that is, there are no failsafe methods of testing that can predict moisture movement in the long run of time. The test measures content of moisture in the snapshot moment they are taken (Concrete Stub Meters and Calcium Chloride dome test). These two test measure to the depth of ½ inch to 1” respectively. In the probe test (they drill a hole and put a sensor plug in place), it measures to the depth of whatever depth the holes is drilled. Each claim some validity to their product and these companies do not like what I’m about to share with you.
Moisture moves about one inch per month vertically through a concrete slab (a residential slab is about four plus inches thick). So let’s say you used a Calcium Chloride Dome test (the most common test requested). It measures moisture about an inch deep. Let’s say you now have a failed floor two months down the line from moisture and blame the installer for your failure. I wouldn’t blame him, he did what the specs told him to do. To be quite honest, as an inspector, most of the calls I go to for moisture, haven’t failed until 4-6 month after installation. Using the one inch per month formula, that moisture came from the subgrade and can’t be measured or predicted. “What about the probe meters?”, you may ask. They’re expensive, and they measure deeper, but they still can’t measure or predict moisture from the subgrade. Right now, I’ll guarantee to you, that I’ll get a lot of hate mail from the moisture meter companies. It is what it is: prove me wrong.
“Ok” you say “we’ll just seal the floor and be done with that problem”. Again, a lot of remedies are available, but no research has been done on the side effects (first if you water seal your flooring, make sure you use the sealer that is compatible with your adhesive and your warrantees). These sealers do stop the moisture from getting to your wood product, for the most part. But they don’t stop the moisture from being drawn to your house. In fact, the whole process enhances the moisture impact. So where does that moisture that you stopped, go? First, the moisture in vapor form attacks the bonding point of the sealer and condenses to liquid. It then (that condensed vapor, now liquid) builds up in the concrete slab until it’s engorged the slab. Then, what was the inert salt (inherent in the concrete) starts to float to the bonding point of the sealer (and has been known to erode adhesives and some sealers). If that’s not enough, the excess moisture, now under pressure, moves laterally and escapes through the unsealed areas (which are your cabinetries and your walls). It then builds up and becomes stagnant and causes mold. How do you stop this moisture? California state construction law (Chapter 2 under Actionable Defects section 896 paragraphs 7-8) states that it’s the responsibility of the original contractor (not a floor installer) to make sure that damaging moisture does not get into the structure in the first place. So quit blaming your installers or floor sales personal on moisture intrusion. Their job is to ensure that you receive a warranted floor, nothing more. But there is a way of stopping the moisture in vapor form from attacking your foundation. It can be done post placement of slab. In the next newsletter we’ll share that gem with you. Remember to send in your questions and we’ll answer them for you.