A moisture meter or a damp meter is a portable instrument designed for measuring the moisture levels in a range of building materials including wood, concrete, brick, and plasterboard.
Early detection of moisture or water damage is essential. Meters help in the prevention of mould growth and structural damage, both are costly to repair and can be detrimental to health and safety.
There are two main categories of moisture meter, Pin type or Pin-less type. Both are handheld and have a screen on the front to display readings. Meters are available in a digital form with a backlit LCD display or alternatively an analogue version with a needle scale. As the meters work in slightly different ways, selecting the best one for the job at hand is dependent on the application and the environment.
A pin-type moisture meter works by measuring the amount of electrical resistance between two points. Pin moisture meters have a pair of sharp metal pins at the top of the device. Once the metal pins are inserted into the material a small amount of electrical current is passed between the two spikes. As we all know water or moisture is a good conductor, so the higher the moisture content the lower the resistance value. The measurement is converted into a % of MC (moisture content) within the material.
A pinless moisture meter works by detecting how waveforms are affected by the presence of moisture in a material. The non-destructive meter works best on a flat surface. Clever internal circuitry produces a signal that is sent out through a sensing area on the back of the device. The signal is emitted in the form of electromagnetic waves. The moisture content can be converted into a scalable format to provide a moisture content reading.
Building inspectors use damp meters to help them identify potentially hidden hotspots behind plaster that can cause damage to structures and buildings from moisture build up.
Being able to determine the best conditions for laying screed, concrete or wooden floors is crucial. Moisture content in materials and the relative humidity in the room must be carefully considered. Failure to do so can cause issues like distortion, cracking and buckling.
Wood naturally has a high moisture content, once dried by air or a kiln meters are used to detect moisture content ensuring the material is dry enough to work with.