Concrete moisture remains the number one reason for flooring failures and therefore, moisture testing and/or mitigation strategies are always recommended to ensure a successful installation. But what are the methods of testing and are they reliable? Here are a the most common testing methods:

Hand-Held Moisture Meters
Contractors often ask if hand-held moisture meters work. The answer is yes, they do, however, it’s important to note that no hand-held concrete moisture meter of any type can give consistently accurate concrete moisture meter readings. Here are few of the reasons why:

Calcium Chloride (Dome) Test
The calcium chloride test method is used to determine the moisture vapor emission rate (MVER) from a concrete slab. Calcium chloride testing involves sealing a small dish of calcium chloride on a clean section of concrete under a plastic dome. The salt absorbs moisture in that environment (and presumably coming from the concrete slab) and the weight gain after three days is used to calculate the MVER. While this method is still specified by many flooring manufacturers, architects, and adhesive manufacturers, the calcium chloride test really only tests the surface conditions of the slab. Here’s what you need to understand about the Calcium Chloride testing method:

Relative Humidity Probe Test

The most reliable moisture testing option is the Relative Humidity Probe Test. It is conducted through the use of in-situ probes which measure RH within the slab. Their depth-specific application has proven to accurately represent moisture conditions in a concrete slab. Their very location within the concrete means they are less susceptible to environmental or ambient changes at the surface.

Mitigation Strategies When Humidity is Too High
In the event that you have a concrete slab with high moisture levels, you will likely have to have a unwelcomed conversation with your end user or general contractor. You will need to explore mitigation strategies to ensure the success of your project. More often than not, the proposed flooring system will need to be reevaluated and the overall cost of the project will increase. Here are some of your options when this happens.