Moisture measuring methods according to the structure

Depending on the structure or sample, measuring moisture can be done through several methods.

For timber, moisture is measured using a moisture meter that measures conductivity: the more moisture in wood, the higher the conductivity. In concrete or anhydrite substrates, three methods for measuring moisture content can be used.

Moisture measurement with oven drying

A sample of the material is analysed in a laboratory where it is oven dried at 70°C. It is then weighed at regular intervals until it reaches a constant weight. It is the total weight loss in relation to the dry mass that determines the moisture content of the sample.

Measuring water content with carbon carbide

This method of moisture measurement consists of putting crushed samples to react. The moisture contained in the samples reacting with the calcium carbide produces acetylene gas, whose pressure is converted into moisture content. This method partially damages the substrate at each measurement.

Measuring ERH with a moisture meter-hygrometer

Part of the NF DTU 53.2 and 54.1 as well as the ASTM F 2170-02 US norm, this method allows measuring Equilibrium Relative Humidity (ERH) and is as precise as the other methods mentioned above, but less destructive to the substrate.
Measurement of the equilibrium relative humidity (ERH) of a material is done by inserting a humidity probe into a wedge in the substrate or box fixed to the surface of a substrate (in case of an heating floor, for example). If the moisture rate is equal to or less than 80%, the finishings can be laid.