Author: Hans-Jürgen Schwarz, NN
back to Moisture Measurement
It is known that thermal conductivity of a building component increases as the moisture content rises. For example, the increase of the volume related moisture content in aerated concrete from 5-10% causes a rise in thermal conductivity from 0.16 to 0.19 W/m2K. If the thermal conductivity of a material and the function of the material moisture content is known, it is possible to determine the moisture content by measuring the thermal conductivity. The best-known method is the Lambda Probe. A resistance wire is introduced into the building component and heated up electrically. From the temperature of the immediate environment of the wire, the moisture content can be deducted with the knowledge of the conductivity. However, there are still some practical problems with this method.