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 Concrete Moisture Testing unique combination system which provides a comprehensive overview and gives the flooring installer peace of mind.
Concrete Moisture Test Methods
Moisture Meters for Concrete test methods include testing the moisture content (%MC) using concrete moisture meters includes non-destructive testing of concrete using impedance meters.
Concrete Moisture Probe
The capabilities of the concrete moisture meters has now been extended even further with the innovative, first of its kind, Concrete Moisture Probe, a.k.a the Determinator. The Concrete Moisture Probe provides quantitative in situ moisture content readings in concrete slabs, down to a depth of 4 inches. These readings can be particularly useful to determine whether the moisture present is coming from below, within or above the slab. This data can help decide the type of mitigation needed to solve the issue. The Concrete Moisture Probe can be inserted in the same hole used for the ASTM F2170 concrete rh test and no hole liner is needed. Therefore it can be easily implemented in the testing procedure, providing essential and instant moisture content data that has never before been available. The Concrete Inspection Kits provide a complete moisture measuring solution for Concrete and Flooring Inspectors, when used with the CME meters will provide instant and precise quantitative measurement of the moisture content (%MC) within the concrete.
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 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.
When Should A Concrete Moisture Test Be Done?
Concrete floor slabs and screeds should be tested regularly during the drying period, to help evaluate and control the drying process, and ensure that the substrate has reached sufficient dryness before the floor covering is installed. The Moisture Meters for Concrete is also an excellent moisture meter for wood floor installation as the external pin probe provides measurements of moisture content in wood. For the purpose of restoration and concrete slab moisture remediation, testing can be done on existing concrete floors and screeds to evaluate the extent and source of water damage, controlling the drying process, and fixing moisture problems in concrete.
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./p>