Consider this scenario: you’re inspecting a home and they have what could be a major moisture issue in their newly finished basement. The drywall is damp to the touch. Areas of the exposed concrete floor are darker in some spots. And there’s a musty smell that’s prevalent. This could be pretty bad.
You go to grab your moisture meter but have two options: a pinless moisture meter vs. a pin moisture meter. Which one do you choose?
Home inspectors regularly face this type of decision -- making a careful choice about the tools they use.
Though both devices are made for surveying moisture, using a pinless (non-invasive) or pin-type moisture meter makes a big difference in how you’ll locate and evaluate dampness.
While both devices detect moisture, the way in which each functions impacts data collected and the depth of an inspection.
As it sounds, a pinless moisture meter doesn’t use probes (pins) to take moisture readings. Rather, pinless meters detect moisture using conductance by either radio frequency or capacitance of a material. Its readings help locate moisture by measuring conductance of the material under test and this can be the highest moisture or the average moisture of its depth of measurement. A pinless meter is ideal for taking measurements in places not easily accessible, such as beneath flooring or behind tile.
Taking moisture inspections in a different direction, pin-type moisture meters provide data on the exact amount of moisture content in wood -- or wood moisture equivalent (WME) -- in other building materials. The distinguishing feature of a pin moisture meter is its pins, or electrodes. Inserted just beneath the surface of material being investigated for moisture, a pin meter reads actual moisture content by measuring electrical resistance between the probes. Since water is conductive, less resistance indicates a higher moisture content percentage.
How do you choose between using a pin vs. pinless moisture meter for a job? Here are six key factors to consider when evaluating both types of damp testing equipment:
With non-penetrating moisture meters, there’s no need to put holes -- though small -- into a surface as you would with a pin-type meter. With materials, such as hardwoods, plaster, or concrete, pin-type moisture meters do leave a small mark where the pins make contact with the surface -- nothing that causes noticeable damage.
Without having to spend time inserting probes into a surface, pinless moisture meters allow for taking readings faster. Time saved on taking individual readings allows inspectors to cover more ground and take more moisture measurements in an area. If higher levels of moisture are found then it would be necessary to use a pin moisture meter to confirm.
In addition, taking more readings quickly at the beginning of a survey helps you zero in on the source of moisture to concentrate your inspection on areas of concern later.
What pin-type moisture meters lack in the speed category, they make up for with accuracy. Compared to pinless moisture meters, pin-type meters provide data that’s much more reliable. Calibrated correctly and with their pins properly pushed into a material’s surface, pin-type meters provide a clearer picture of moisture content within a substance.
That’s not to say that non-invasive meters are inaccurate. They just take moisture readings for a different purpose: to locate the presence of moisture. Their readings should be interpreted as such. Pin-type meters confirm a pinless meter’s readings and tell exactly how much moisture is in a material.
In a sense, pin-type moisture meters are a Swiss Army knife of sorts. Most pin meters feature removable electrodes that can be swapped for other accessories that are handy for inspections.
Common attachments include:
Taking a moisture content reading you feel confident in may require additional verification. With a pin-type meter, you’re able to test the same material twice and consistently get the same reading.
While non-invasive meters are used to take multiple readings in an area, they’re not evaluating a material in the same way as a pin-type meter. Nor are they measuring actual moisture content -- they’re helping you locate moisture.
When presenting the results of a home moisture survey, those footing the bill for repairs (homeowners and potentially insurance companies) are more concerned with the damage done by moisture.
Readings from a pin-type meter tell you there is sufficient moisture that can lead to decay or mold. Using a measurement scale that’s much more refined than those of non-invasive meters, pin-type meter readings quantify more precisely the levels of moisture in a material.
Moisture readings taken from a pinless moisture meter are still helpful -- they show your efforts to locate the source of moisture during an inspection.
It is important to understand that using a non invasive meter may pick up conductive materials such as metal behind the surface so always use a pin meter on the surface to verify if you are seeing moisture not metal. Think about corner beading in drywall construction.
Back to our original scenario.
When choosing between pin vs. pinless moisture meters for an inspection, what do you do? The answer is simple: take both.
With both meter types in your tool kit, you’ll have the equipment to provide an accurate and representative portrait of moisture presence within a material and space. Both meter types work hand-in-hand in taking complete moisture surveys.
The Protimeter ReachMaster Pro takes the hard work out of taking moisture readings. And it helps keep you safe. Learn more:
Or check out the Protimeter Surveymaster -- the de facto standard in restoration and inspection as it incorporates both pin and pinless measurement in one handy moisture meter.