Waiting vs. mitigating. It’s a moisture dilemma most flooring installers face when encountering moisture challenges on the jobsite. Accurate concrete moisture testing is essential, but even under ideal conditions, concrete drying takes around 30 days per inch of slab depth.
So how do you determine the next steps? First, you need accurate concrete moisture testing. This will arm you with solid data so you can choose the most cost-effective mitigation method. It makes dollars and sense.
Fresh concrete mix contains water to help it harden or cure. But after initial hardening, concrete continues releasing moisture. If you install flooring over a wet subfloor, it can cause total flooring failure from issues like blistering, bubbling, delamination and warping. That’s why flooring professionals consider moisture mitigation systems when pressed for time.
If concrete is too wet to install flooring, you have two choices: 1. Wait until it’s dry, keeping the area enclosed with the HVAC system and a dehumidifier running; or 2. Apply a mitigation product, using moisture readings to buy one in the right price range for the slab’s RH level.
An epoxy system is generally considered an effective method for concrete moisture mitigation. However, effectiveness varies widely across all moisture mitigation systems, so it’s smart to purchase one from a highly reputable company.
With all the different types of moisture mitigation products, protection levels and prices out there, how do you choose the right one for the job? The short answer is: As long as your concrete moisture readings are accurate, you’ll be able to use that data to guide your next steps.
Concrete moisture testing helps you determine what level of mitigation you’ll need, but it’s important to note that some moisture-testing tools work better than others. Let’s break down some of the pros and cons of three main tools: calcium chloride testing, concrete moisture meters and relative humidity testing.
Calcium chloride (MVER) testing: The upside is test kits are inexpensive and testing procedures are non-invasive. On the downside, this process is very labor-intensive and kits are not reusable, so costs add up over time. Some even argue it’s often inaccurate and lacks scientific backing and only reveals moisture in the upper portion of the slab. For some flooring manufacturers, it will not meet the warranty requirements.
Regarding concrete moisture meters, the main benefit is they meet ASTM F2659 guidelines for identifying moisture hotspots, although it does not provide information to make a final decision on whether or not to install the floor covering in most cases. Other benefits: it’s non-invasive, gives instant readings and is reusable across projects.
Conversely, concrete moisture meters are not precise for deep measurements and don’t meet most flooring manufacturer requirements for moisture testing before installation. Moreover, these testing meters can be very expensive.
Lastly, relative humidity (RH) testing is considered the industry gold standard for accurate concrete moisture testing. It’s able to detect hidden moisture deep inside a slab and meets ASTM F2170 guidelines for floor installation decisions. Test probes are often reusable on the same project. On the downside, RH testing kits can be expensive ($400-$1,500 or more for a starter kit.) In addition, RH testing is invasive; in-situ testing requires drilling a small hole in the slab.
In a perfect world, concrete will dry on your schedule. However, if it fails to dry fast enough, you’ll need a moisture mitigation product. The right system will provide results for your specific situation. It’s your defense against costly delays and callbacks.
Jason Spangler is sales manager for Wagner Meters.
