A Complete Guide to Moisture Meters

What is a Moisture Meter?

Moisture meters (otherwise known as moisture detectors) are used to measure the amount of water within a material sample. This measurement allows the user to find out whether the moisture levels are appropriate, or if adjustments need to be made.

In particular, property inspectors may be keen to identify the levels of moisture due to the risk of damage associated with damp. Alternative use may be made by furniture builders keen to ensure the best possible quality.

Moisture meters typically feature digital screens that allow quick readings to be taken. The reading may indicate whether there is some disparity in the moisture level in relation to a pre-defined limit.

Moisture meters may be used to assess materials including:

• Wood

• Concrete

• Drywall

• Paper

Excess moisture may result in the degradation of the material, so it is important to take meter readings. Moisture meters are essential tools for professionals who deal with property maintenance, wood fuel, and stove installation, to name just a few common applications.

Types of Moisture Meter

There are two main types of moisture meter - pin and pinless. These types of testing equipment are each suitable for specific purposes and are unique to the user’s requirements in measuring the level of moisture content.

What are Moisture Meters Used for?

As previously mentioned, moisture meters measure the level of electrical resistance between two set points. However, pin-type moisture meters only measure the moisture content (MC) of the set point between the two pins. Repeat readings are required to establish the MC when using a pin-type meter. Conversely, pinless moisture meters transmit an electromagnetic signal that allows for the assessment of a greater material area.

Moisture Meters for Caravans

The level of interior damp is a common concern for caravan owners. This is because the sealant used in caravan construction is known to deteriorate over time, allowing moisture in. However, a variety of damp meters can be used to monitor moisture levels and identify the percentage of moisture content in different areas of the caravan.

You should be aware that a moisture reading of 0-15% is quite normal and gives no cause for concern. However, moisture readings in excess of 15% indicate the need for further inspection. Levels between 25-30% indicate that there may be water ingress, meaning that remedial work could be required. It’s also worth bearing in mind that environmental conditions will have an impact on the moisture readings, with higher levels of moisture expected on wet days.

Moisture Meters for Soil

Portable soil moisture meters are purpose-made to identify levels of moisture within soil, compost, and vegetation. Such meters are commonly used by gardeners, farmers, and conservation experts to ensure that environmental conditions are ideal for growing plants, flowers and crops. It is advisable to take readings in a few different areas around the vegetation to ensure accuracy across the board. You can also use this sort of meter to assess the type of soil (whether moist or freely draining) and calibrate irrigation systems.

Moisture Meters for Plants

It is essential to ensure that indoor and outdoor plants have enough water. Plant moisture meters can be used to monitor the dampness of soil, letting you know if you need to add water. Moisture meters that indicate whether the soil is wet, moist, or dry at the root level are considered the best option for large potted plants. There is a variety of easily affordable moisture meters available that can be used to gauge the moisture level of houseplants. However, it would be worth investing in a robust meter featuring a long stem to measure moisture levels in clay and hard soil.

Moisture Meters for Walls

A range of moisture meters can be used to accurately assess levels of moisture within different types of walls. These portable devices indicate whether there is any evidence of rising or penetrating damp within foundation walls, floors and timbers. They can also be used to assess the dryness of surfaces before papering and tiling work takes place.

How Does a Moisture Meter Work?

Moisture meters can be used to assess moisture levels within a wide variety of materials. Some moisture meters provide analogue readings, while others provide digital.

Moisture meters commonly feature colour indicators that light up in accordance with the detection of different moisture levels. The green light indicates dryness, the yellow represents moderate moisture, and the red denotes high moisture levels.

As previously mentioned, moisture meters are available with and without pins. The pin-type moisture meter operates on a resistance principle and allows for the basic measurement of electricity circulating through a substance. This type of meter can be used to effectively distinguish surface and ambient material conditions. However, the use of a pin-type moisture meter may result in material damage.

The pinless or non-invasive moisture meter operates on the principle of electrical impedance. It allows for accurate readings to be taken without causing any damage to the material.

How to Use a Moisture Meter

For accuracy, you should calibrate the moisture meter prior to taking any readings. The exact process of calibration will vary, depending on the type of meter that is being used. However, the majority of pinless meters can be calibrated with a purpose-made calibration block or kit.

Once the device is calibrated, how to use a moisture meter efficiently and effectively will depend on the specific type of meter you are using.

The process of using a pin-type moisture meter is as follows:

A pinless moisture meter should be used as follows:

Moisture Meter Brands

There is a wide range of available brands and manufacturers offering high-quality moisture meters. This variety includes both pinless and pin-type moisture meters which are suitable for applications including woodworking and property inspection.

FAQs

Are Moisture Meters Accurate?

Factors such as the type of material being assessed, the corresponding moisture meter scale, and the level of maintenance all have a bearing on the accuracy of the moisture meter. A high-quality meter can provide readings with an accuracy of up to 0.1% in relation to the material’s moisture content. As previously mentioned, you should calibrate the meter before use to ensure that it is as accurate as possible.

What is an Acceptable Moisture Reading?

The acceptability of the moisture reading depends on the type of material being assessed. For instance, different levels of moisture will be deemed acceptable in wood, depending on the intended use and the environment surrounding the area set for installation. Oven drying and other methods may be used to establish levels of accuracy.

What is the Best Moisture Meter for Firewood?

The pinned variety is recommended for checking wood that you are simply going to burn. Your chosen moisture meter should offer a good level of accuracy in checking the moisture content range - maximum moisture content of 20% is usually recommended for firewood.

What is a Normal Moisture Level in Walls?

The normal or safe level depends on what the wall is made from. As an example, drywall will ideally have a moisture content of under 1%. However, it is worth keeping in mind that the levels of ambient humidity and surrounding temperature will also have some bearing on the amount of moisture that is present.

Can a Moisture Meter Detect Mould?

A moisture meter can’t directly detect the presence of mould. However, you can use the meter for a general inspection, identifying areas where there is an increased risk of mould. In cases where you do suspect the presence of mould, it’s wise to consult an expert for further guidance. In terms of the best meter to use for the task, moisture analysers are typically preferred for mould detection.