Home Inspection Training: Using a Moisture Meter

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There’s something to be said for understanding the fundamentals of what you’re doing. 

Ever tune in to watch your favorite NFL team take the field for the season opener -- kicking off what’s sure to be a championship year? 

But despite an amazing run last year and a very promising preseason, there’s something off about the players. 

The wide receivers go too wide. The running backs are literally running back in the wrong direction. And even with plenty of open targets, your team’s quarterback is throwing the ball like he’s never held one before. 

Each player is playing their own game, and it’s not working. Frustrating, isn’t it? 

Just like a starting NFL player, understanding the fundamentals of a job -- and the tools of the trade -- matters. The same goes for a home inspector conducting a moisture survey. 

The MVP of equipment used in a home moisture survey, a moisture meter is one of the most important items a home inspector should be absolutely proficient in using. 

Home Inspector Training & Moisture Meters 101

The foundation of any elite athlete is a mastery of the basics. The same applies to home inspectors using moisture meters. Without having command of a meter’s base-level functions and upkeep, a home inspector will almost certainly have difficulty completing a home moisture survey effectively. 

Before diving into the specifics for each moisture meter type, here are a few basics any moisture meter user should be aware of: 

  • Have the right mindset about your meter’s purpose. Contrary to popular belief, a moisture meter is not a diagnosis tool. Rather, it helps an inspector make an informed call about moisture’s presence within a space or material. If your meter is giving you a high reading, that merits further investigation -- dampness may not be the reason for the measurement; metals and salts cause false-positive readings.

  • Regardless of the meter type you’re using, take multiple measurements. Taking the few extra seconds for a second reading confirms the initial measurement and helps you make a more thorough determination of moisture’s presence. 

  • Compare readings for moisture against those taken on a known dry material. Measurements taken on a dry material in the building give you a baseline to effectively gauge moisture elsewhere in it. 

  • Check the calibration of your meter before each use. A simple process that only takes a few seconds, a calibration check ensures your meter is ready to take accurate measurements. 

  • Become familiar with meter attachments and their appropriate uses. For instance, extension probes help you take readings in hard-to-reach spaces -- such as the back of a cabinet -- while keeping your meter safe in hand. 

Home Inspector Training & Moisture Meter 201: Understanding Meter Types and Their Uses 

To complete a thorough and accurate home moisture survey, you’ll need to be well-versed in the meters needed to complete the job. Think of it as understanding when to use cleats depending on playing field conditions.

In any home moisture inspection, your tool kit should include two meter types: pin and pinless. While both meters help you gauge the extent of moisture within a material or space, they serve different purposes and are ideal for different parts of a home moisture inspection. 

Pin-Type Meters

Designed to measure actual moisture content, pin-type meters take readings by direct contact with a material. A pin-type meter’s probes determine moisture content by measuring electrical resistance between the probes (pins). Since water is dampness-conductive, less resistance indicates a higher moisture content percentage.

Pin-type meter readings are representative of moisture content in wood, or wood moisture equivalencies in other materials. Their measurements should be used to confirm the readings found by a pinless meter.

Aside from the basics listed above, the #1 thing to know about how to use a pin-type moisture meter is: Do not jam its pins into the material being tested.. A pin-type meter’s probes only need to make contact with the surface of a substance to take a measurement. 

Pinless Moisture Meters (AKA: Non-Invasive Moisture Meters) 

This meter type is meant to help you locate moisture within a space and investigate further with a pin-type meter. They’re used during inspections to check for moisture in spaces that can’t be reached with a pin-type meter, such as behind a wall or beneath flooring. 

Using radio frequencies or capacitance of a material, a pinless meter detects issues by assessing the average moisture of a material within its depth of measurement. Non-penetrating moisture meters don’t tell you actual moisture content -- they help confirm the presence of moisture within a substance or area. Use in areas such as behind ceramic tile or vinyl floors where there are no visual signs of water. 

Home Inspector Training: Simplifying Through Consistency & Cohesion 

One of the best things you can do to conduct inspections efficiently is to use the exact same meters -- and this includes any backups or spares. 

With identical moisture meters, you’ll never waste time figuring out how a moisture meter works because it’s completely different from the one you used last time. 

What’s more, identical meters allow you to take standardized measurements. When it comes time to prepare the inspection report, there’s no need to make adjustments because of using meters of different brands with different measurement scales. If there’s a need to reinspect, readings are repeatable. 

Home Inspector Training for the Win (Accurate Surveys) 

While no two homes are the same, the foundation moisture survey shouldn’t be different. Like a football player practicing catching the ball before the first game of the season, having a command over the fundamentals of the job -- and the required tools -- is critical to completing successful inspections. 

Take Home Inspector Training to the Next Level 

Dive into exactly what you need to know to collect & interpret moisture readings you can be confident in. Download our free guide, How to Measure Moisture in Buildings: 

How to Measure Moisture in Buildings - Protimeter