Concrete Moisture Meters and Humidity Sensors

The Importance of Concrete Moisture Testing

Tramex Concrete Moisture Meters provide solutions for concrete moisture testing and screed moisture testing and help avoid moisture related problems that can cause floor failure.

For concrete and cementitious screeds to receive a floor covering the base must be suitably “dry enough” to prevent damage to the flooring material and to ensure a proper bond with adhesives.

Water is a vital component in the manufacture of concrete and the concrete must be kept moist during the critical curing phase to ensure the intended concrete strength. However, excess moisture in the substrate is the most common cause of floor failures, costing billions annually and causing major disruption to home and business owners.  This is why the best moisture meter for concrete is recommended.

Concrete moisture testing and screed moisture testing is simple using Tramex’s unique combination system which provides a comprehensive overview and gives the flooring installer peace of mind.

Tramex Concrete Moisture Meters and Probes

Tramex concrete moisture test methods include testing the moisture content (%MC) and Relative Humidity (%RH) using concrete moisture meters and probes:

• non-destructive testing of concrete using impedance meters, the Concrete Moisture Encounter 5 and Concrete Moisture Encounter X5, 
• in-situ impedance probes, the Concrete Moisture Probe/Determinator for in-situ moisture content in concrete
• and the testing of relative humidity (%RH) using in-situ Hygro-i2 RH sensors. 

Gravimetric-based, Quantitative In-situ Testing of Concrete with the Concrete Moisture Probe

The Concrete Moisture Probe operates on the principle that the electrical impedance of a material varies with its moisture content. The CME instrument is pressed onto the CMP cradle which is pressed onto the material surface with the pins fully compressed and the probe inserted into the pre-drilled hole (using a 3/4 inch / 19mm drill-bit) to measure the moisture content. The electrical impedance is measured by creating a low frequency alternating electric field between the electrodes and the probe, to a depth of up to 4” (100mm). This field penetrates the material under test. The very small alternating current flowing through the field is inversely proportional to the impedance of the material. The instrument detects this current, determines its amplitude and thus derives the moisture value.
These in-situ %MC readings are directly comparable to the top surface layer non-destructive %MC readings, and the comparison can be particularly useful to determine whether the moisture present is coming from below, within or above the slab.

• If readings are higher at the surface than the in-situ readings in new concrete, this may be a result of dew point issues, where condensation has formed at the surface.
• If readings are higher at the surface than the in-situ readings in older concrete, it may be the result of an old vapor or moisture barrier at the surface causing moisture to collect in the top 3/4 inch (20mm) layer below the surface. 
• If in-situ readings are more than 1%MC higher than the surface NDT readings, this may be due to moisture coming up from the concrete due to a lack of subfloor barrier.

The hole that is used for the in-situ %MC readings with the Concrete Moisture Probe can now be used for the in-situ %RH probe hole liners.

Concrete Moisture Testing at the time of installation

Installation Quick Check tests should also be done at the time of installation. This involves testing the ambient conditions and the moisture content in the top surface layer. Ambient Conditions are important and often overlooked when measuring the moisture conditions of a concrete slab to check if it is dry enough to accept a floor covering or coating. It is important to remember that moisture moves from Hot to Cold and that Concrete is generally 1-2 degrees cooler than the ambient temperature. If the temperature of the slab is too close to Dew Point, the upper portion of the concrete can become saturated with the moisture that moves from the warmer air to the cooler concrete slab.