Moisture meters are invaluable tools for detecting hidden water damage before it becomes a serious problem. These devices can save you from costly repairs by finding excess moisture in walls, floors, and other building materials. In the video above, Ross Trethewey demonstrates a few types of moisture meters and explains how to interpret their readings.
How Moisture Meters Work
Moisture meters are designed to measure the water content in various materials, primarily wood and drywall. They provide homeowners with a way to detect potential damage or leaks that may not be visible to the naked eye.
Moisture meters operate on the principle that water conducts electricity. When moisture is present in a material, its electrical properties change. Moisture meters measure these changes, allowing you to see if moisture is damaging your home.
There are two categories of moisture meters: ones that use pins and ones that do not. With pin meters, the device sends an electrical current between two metal pins inserted into the wall. The resistance to this current indicates the moisture level. Pinless meters use electromagnetic waves to measure moisture content without penetrating the surface.
Types of Moisture Meters
There are several types of moisture meters available:
- Thermal imaging cameras: Detect temperature changes behind walls, which often indicate moisture presence
- Electromagnetic sensors: Scan surfaces without causing damage, and work with various materials
- Pin meters: Feature two sharp points and are highly accurate, but only work for drywall and wood
- Combo meters: Combine pins and electromagnetic sensors for a more complete moisture detection
Using a Moisture Meter
This handy tool can identify potential water issues before they escalate into major problems, so make sure you know how to use it.
Before Measurement
Before taking a reading, take the following steps:
- Make sure the meter is calibrated correctly
- Clean the surface area you plan to test
- Choose the appropriate setting for the material you’re testing (if applicable)
Take the Measurement
To use a moisture meter effectively, do the following:
- Place the meter firmly against the surface or insert the pins into the material
- Hold the meter steady for a few seconds
- Read and record the measurement
- Take multiple readings in the same area to get a broader reading for accuracy
Interpret Moisture Meter Readings
Now that you’ve taken the measurement, you need to know what a normal moisture reading should be.
Moisture levels for drywall and wood:
- 6-9%: Normal moisture content
- 10-14%: Slightly elevated, monitor closely
- 15-20%: High moisture, investigate further
- Above 20%: Very high, immediate action required
Common Uses for Moisture Meters
Moisture meters have many uses in home maintenance and improvement projects.
Detecting Water Damage
One of the main uses of moisture meters is identifying water damage in walls, ceilings, and floors. Regularly checking these areas, especially after heavy rains or plumbing issues, can help you catch problems before they become more severe.
Assessing Flood Damage
After a flood, moisture meters can help determine the extent of water damage and monitor the drying process. This information is especially helpful for proper remediation and preventing mold growth.
Evaluating Wood Moisture Content
For woodworking projects or when installing hardwood floors, moisture meters check that the wood has the right levels of moisture content. This prevents future warping, cracking, or other moisture-related issues.
Inspecting HVAC Systems
Moisture meters can also be used to inspect HVAC systems for leaks or condensation issues. Checking that your HVAC system is free from any water issues can prevent costly repairs and improve system efficiency.
Choosing the Right Moisture Meter
For most homeowners, a combo meter that has both pin and pinless functionality is easy and versatile for different areas around the house. These meters typically cost less than $100.
Factors to Consider
When choosing a moisture meter, consider:
- The types of materials you’ll be testing: If you’re testing various materials like wood, drywall, or concrete, you’ll need a versatile moisture meter that offers different measurement modes or probes for each material type. Specialized meters, such as pin-type for wood, cater to specific needs.
- The frequency of use: For regular use, investing in a durable and reliable meter will help ensure consistent performance and longevity. Regular use may also justify a higher-end model with advanced features and better build quality.
- The level of accuracy required: High-accuracy needs, such as in scientific research or quality control, call for precision meters with advanced calibration options and detailed readings. Simpler, more affordable models should be suitable for most basic home inspections.
- Your budget: Budget constraints will influence your choice between basic, entry-level meters and higher-end models with advanced features. Higher-priced meters often offer better accuracy, durability, and additional functionalities, while more budget-friendly are fine for less demanding applications.
Maintaining Your Moisture Meter
Moisture meters are relatively low-maintenance devices, but you should still make sure they stay in good condition.
Calibration
Regular calibration is necessary for accurate readings. Many meters come with a calibration check feature or a calibration block. Follow the manufacturer’s instructions for frequency and the right procedure.
Storage and Handling
To keep your moisture meter in good condition, take these steps:
- Store it in a dry place at room temperature
- Avoid dropping or rough-handling it
- Clean the sensor or pins after each use
- Replace batteries quickly when needed
Testing and Replacement
It’s a good practice to test your moisture meter periodically against known moisture levels to check its accuracy. If your readings become inconsistent, it may be time to replace the device. Constant exposure to different environments and materials can wear out the meter over time.
When to Call a Pro
While moisture meters are useful for homeowners, there are situations where professional help is the right call.
Signs of Severe Water Damage
If you consistently get high readings (above 20%) or notice visible signs of water damage such as warping, discoloration, or mold, it’s time to call in a professional. These experts have more advanced equipment and the expertise to address serious moisture issues.
Mold Concerns
If you suspect mold growth, especially in hidden areas, we recommend hiring a professional mold inspector. They can perform thorough assessments and recommend the right remediation strategies.
Persistent Issues
If moisture problems persist despite your attempts at multiple fixes, call a professional. Constant moisture can indicate underlying issues such as faulty plumbing or poor insulation that need immediate attention from an expert.