Abstract

In Denmark probes made with electrodes placed in a small plywood disc or a small piece of beech wood have been used for long-term measurement of moisture content in wooden constructions, especially roofs. The probes are embedded in the wood structure where the measurements are to be made and are equipped with wires in order to make remote measurements. This makes it possible to measure moisture content in closed cavities etc, where it would be difficult or impossible to use hand-held moisture meters. The method is described in NORDTEST method 420 "Building materials, wood: Moisture content".

The paper describes the experiences gathered during the many years of use. A large amount of constructions have been equipped with this type of sensors giving experience about the usefulness and the long-term stability of the sensors. Besides, different investigations have taken place regarding, for instance, the influence of the shape and dimensions of the probes, the materials used for electrodes and the way of connecting the wires to the electrodes. For some years it has been feasible to perform "continuous" measurements with a datalogger. An example of results achieved in this way is given. The precision, the advantages and drawbacks experienced during the use etc. is discussed. Comparisons are made to what can be achieved by placing electrodes directly in the wood to be measured

Nordtest Method, NT Build 420 (1993), Building Materials, Wood: Moisture Content.

• measurement: moisture content

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