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Moisture Meters Guide and Tips

Guide and Maintenance tips to Common Mistakes to Avoid With Moisture Meters


Diagnose or prevent moisture problems
The moisture meter is a common tool utilized by many professionals in the home inspection and construction industries. Designed to enable users to accurately reveal moisture content levels in a range of materials, moisture meters are generally easy to use, It can be found at online discounters for around $60 and require only a general understanding of its function.

However, without a proper understanding of the many specifics and features of each particular moisture meter, as well as a sufficient knowledge of how a variety of factors can also affect moisture level readings, it can be easy to use the tool improperly, thus resulting in a reading that is not entirely accurate.

Moisture is a major concern to those in the construction and inspection industries, more importantly boat buyers and proper usage is essential to ensuring that tests are conducted efficiently so as to provide the best possible results.

There is a range of moisture meters available for testing a wide selection of different materials and substrates. Moisture will affect all materials differently, from concrete to sheetrock to dozens of types of wood materials.

Common Mistakes

Even with a vast knowledge of how to use moisture meters properly, there are still many common mistakes that can be made.

Not following a standard set of guidelines and main instructions when using moisture meters and taking readings can result in future problems at a later point in time. Avoiding the following mistakes when testing wood or other materials for moisture content ensures that many problems and unnecessary costs can be easily avoided.

At first Make Sure You Are Using the Right Moisture Meter for your needs.

Check For Proper Calibration

As mentioned above, different materials require different calibration settings.

Some moisture meters have automatic built-in calibration for different wood species and other substrates; other may need manual calibration. It is also wise to periodically test your moisture meter on a material with a steady level of moisture. This will help you to better determine if calibration settings are still correct or if they have somehow been altered or lost.

Many professionals have fallen into the habit of relying upon one type of moisture meter, yet many factors can affect readings in different situations. Different types of wood and other materials can yield vastly different readings, and knowledge of the material you will be testing beforehand will allow you to correctly choose the best moisture meter for the job. Some moisture meters, although capable of testing many different substrates, are designed specifically for wood testing, while other may be more ideal for testing.

It is also important to know whether or not you will need a pin or pinless moisture meter. Pins can leave holes or visible damage and if someone is going to be unhappy about seeing unsightly holes in their walls or flooring, then you'll want to go with a noninvasive moisture meter.

Proper calibration

Additionally, proper calibration of the moisture meter for the material being tested is key to ensuring an accurate reading.

Maintenance tips & advice

Other maintenance tips include keeping pins in great condition and replacing heavily used pins, so as to get more accurate results.

Don't Settle for Just a Few Readings

Many contractors, inspectors, and other professionals fall into the trap of relying upon just a few readings to gain a general determination of moisture levels throughout the complete area or material. This is unwise, as it can cause you to miss areas where leaks or water damage have occurred. Most moisture meters can deliver results very quickly, so it should not be too much of a hassle to be extra thorough and take additional readings.

Make Sure You Understand the Results

The key to understanding the results of a reading lies in understanding the particulars of the material being tested. Many moisture meters come with charts that can be consulted to provide you with accurate information relative to the readings and the substrate. A reading for one type of material may mean something completely different for another material, and different species of wood all have their own specifics and optimal moisture content levels.

Testing moisture content

Typically, for testing moisture content in wood, a pin type moisture meter will be used. The conductance meters use an invasive method of performing a test, by way of pin shaped electrodes of varying lengths. These pins usually range in size from 3/8-inch to 3 inches, and are inserted into a wood material. The pins then measure the conductive current that runs between the two electrodes and the resistance to the flow of the direct current through the material. This reading is converted to a moisture content result. A high conductance reading means that more moisture is present within the wood.

Pin type meters

Pin type meters, also referred to as invasive moisture meters, are equipped either with insulated and non-insulated pins. The insulated pins are usually longer than non-insulated pins, and are coated with a non-conductive material except at the tip. The long pins are usually driven into the wood using a slide hammer device or similar tool, and take readings only at the conductive area of the pins. Non-insulated pins will take a moisture reading between the pins wherever the moisture presence is highest.

This can sometimes result in very different readings depending upon how far into the wood the pins are inserted and where along the length of the pins the reading occurs. For more accurate readings at precisely specific points and depths in the wood, insulated pins are a more ideal solution.


Conductance meters should also be adjusted for the different types of wood that may be encountered, and the area temperature can also be a factor that affects the readings. The manual that accompanies a moisture meter should provide instruction on how to adjust the meter for these specifics. Some engineered woods contain glue or resins that may also affect the readings.

Non-intrusive Moisture Meters

The difference between these meters and the pin-type meters is that it does not penetrate the material and does not utilize pins to take readings.

Non-intrusive meters can also be used to measure moisture content in wood and materials. Instead, the meter is placed against the material, and a plate with a specific range and depth of sensing ability takes an average reading of the entire area that can be read. This type of meter is also referred to as a capacitance meter. The capacitance moisture meter has the ability to take several readings in a short amount of time.

The Total Dissolved Solid (TDS) Meters

When dealing with conductivity, the Total Dissolved Solid (TDS) in a liquid is useful to know but often hard to identify. TDS Meters effectively help determine the total dissolved solid and, therefore, the liquids conductivity. Check out PE Facts to find out how to get the most reliable results from your TDS Meter!

TDS is defined as the Total Dissolved Solid in a liquid solution. The Total Dissolved Solid is considered the total weight of all solids that are dissolved in a given volume of water, expressed in units of milligram (mg) per unit volume of water (mg/l). It is also referred to as parts per million and is directly related to the cleanliness of water and water purification systems.

Dissolved solids are typically any salts, minerals, metals and even dissolved gases present in water. It also includes anything else present in water other than the pure water (H2O) molecule and suspended solids. Dissolved solids also consistently contribute to the conductivity of a solution.

Conductivity can be defined simply as the measure of how well the electricity, or current, flows through a solution. It is measured in siemans, micro (S), or milli (mS) per cubic Centimeter (cm). In general, the more ions in a liquid, the easier it is for a current to flow through it. For instance, it is much easier for a current to flow through salt water than through distilled water, or a similarly pure liquid. The following are conductivity levels of some common liquids.

Deionized Water - 055S/cm, Drinking Water - 100S/cm and Ocean Water -53 mS/cm

Different dissolved solids give various conductivity readings. This allows us to use conductivity to determine what materials are dissolved in a solution. There are instruments available to measure conductivity and, therefore, they can also identify the dissolved solid. Dissolved solids are measured in parts per million (ppm) or parts per thousand (ppt) and are used in various chemical and industrial procedures.

Dissolved solids can produce a variety of problems such as causing water to taste bitter or salty, causing corrosion of plumbing fixtures and piping, causing the effectiveness of water filters to be reduced, along with poor performance in the processes of the manufacturing industries.

There are numerous manufacturers of high quality TDS/Conductivity Meters that provide reliable water testing an analysis. These instruments are reasonably inexpensive and are calibrated and certified according to NIST standards. Some meters have features such as automatic temperature compensation and push-button calibration functions.

Any of the available instruments will provide excellent performance given that you read, understand and adhere to the manufacturer's guidelines. It is particularly important to follow the manufacturer's instructions when calibrating your instrument in order to guarantee that it is operating to its fullest potential.

Manufacturers cannot stress the importance of regularly maintaining their instruments enough. Proper maintenance, outlined in the instruction manual, is the only way to keep instruments functioning properly, accurately and reliably for a long lifespan. In order to help users do so, manufacturers provide calibration, buffer, and storage solutions as well as a technical service support team who can be called anytime for assistance.

Manufacturers usually give a certificate of analysis with their maintenance solutions showing the date of manufacture, lot number, accuracy and expiration dates.

Calibration (Typical):
The tester is factory calibrated. However, to guarantee accuracy, calibrate regularly according to your specific instrument's manufacturer instructions -example below. Select a calibration standard appropriate for your tester:

ECTESTR LOW:From 200 to 1990 S

ECTESTR HIGH:From 1.0 to 19.90 mS
TDSTESTR LOW:From 200 to 1990 ppm

TDSTESTR HIGH:From 2.00 to 10.00 ppt

It is best to select a Standard close to the test solution value.

Open the battery compartment lid (end with lanyard loop). The Increment (INC) and Decrement (DEC) calibration keys are the two white buttons.
Rinse the electrode in deionized water, then rinse it in the calibration standard, then dip it into a container of the calibration standard.

Switch the unit on (ON/OFF key). Wait several minutes for the display to stabilize.
Press the INC or DEC keys to adjust the reading to match the calibration standard value.

After 3 seconds without a key press, the display flashes 3 times, and then shows "ENT". The tester accepts the calibration value and then returns to measurement mode.

Replace the battery cap.

Tester Maintenance:

To enhance performance, rinse the electrodes in alcohol for 10-15 minutes.

If the low battery indicator appears, or if readings are faint or unstable, replace all batteries.

If you experience drift, occasionally let the electrode dry fully.

If you need a new electrode, refer to your manufacturer's instruction manual concerning replacements.


Many different factors must be taken into consideration when taking readings with either type of moisture meter. In addition to the specifics of each type of meter, the depth capacities of each meter must also be known, as each meter can be calibrated to different depths.

Additionally, the presence of surface moisture on a material can result in a widely skewed reading, and pins on pin-type meters should be kept in top condition. Replacement pins can be purchased for many meters to ensure accurate readings. When using pin-type meters, you should be aware that the pins obviously leave holes in the material. If this is a possible issue, a non-invasive moisture meter should be used.

Most invasive moisture meters are designed to be used parallel with the direction of the wood grain, but not all. The manufacturers guidelines should detail in which position the meter should be used for best results.

For non-invasive moisture meters, you should be aware of the size and depth of range that the meter is capable of reading, and the meter should always be in full contact with the material.

For construction and inspection trades, providing accurate readings and the accompanying documentation of the results can be a key component of a professional installation or inspection.

Related Items: Diagnose or prevent moisture problems: How to Prevent Mold During Winter Storage, tips & advice.

Recommendations on a cheap but well functioning moisture meter

In fact, boaters needs are to track down where the leaks are coming from and where I'm going to need to replace core when I get to the decks after rainy season. A few hundred on a moisture meter is cheap insurance ,especially when buying a used boat.

Moisture in the core is much more costly than the meter that allows you to find it before you buy a boat with a problem, and it also shows you when a good boat might be due for a small core replacement job before it becomes a big expensive core replacement job.

GRP-33 Moisture Meter

Electrophysics GRP-33


Actually, 15 to 20 percent is like a damp sponge,,20 to 25 percent is like a wet sponge that has to be twisted to release the water,,30 plus and its like taking a sponge straight outn of a bucket of water. You can have wet core but the laminate is still adhered to it and will tap out sounding solid, it's just a matter of time before delamination occurs once you have water intrusion in the core.

Biggest problem with water intrusion is nobody bothers to reseal their fasterners and mechanical hardware every 5 years and most production companies use silicone which is not good.

Skipper Plus by Tramex

Moisture meters are very unreliable! The best thing you can do, rather than spending the money, is to the old-fashioned hammer tap! If you feel like you don't have a good ear for this, ask someone who has been around a while. You're listening for a hollow sound, a thud that sounds different from the parts of the hull/deck that you know are solid.

Skipper Plus - afford a xray machine to check other things you can't see

A Tramex Plus moisture meter will read 3/4" through a solid material to get a reading without making any holes. You just can't get any measurements through a metal surface. Call a Water Restoration company to see if they will help you out. Especially if they have a FLIR thermal imagine camera.

Measuring Instrumentation