Window around high humidity alarm

Hello, All

This humidity alarm will happen when I did some house inspection and it around the windows.

Do any inspector can explain why it happen and could I call it water leaking or air leaking?


Many moisture meters will go off around metal corner bead, etc.


Hello Chang,
The instrument in your hand , the MT-28 pinless moisture meter, will approximate the moisture content of the selected material. It has a senor pad that emits electromagnetic waves. You will get bad data if you use this tool incorrectly or assume that you are measuring something that you are not.
Pinless moisture meters do not work well on rough surfaces or on materials that have embedded metal such as corner bead or drywall screws, etc. You will get a false high reading when the instrument is in close proximity to ferrous materials.

The MT-28 does not measure humidity, but it is available for $30 on Aliexpress (Chinese eBay).

The instrument in your hand does not directly measure moisture. It measures capacitance. (pin-type moisture meters measure resistance). If you get an alarm value, you must investigate further to figure out if the alarm was triggered by moisture or by getting close to another condition that reduces capacitance.


I suspect that’s new construction. Sheetrock mud will have higher moisture content until it dries completely. Conversely, metal corner bead will ping at 100 percent.


You are in contact with drywall metal corner bead and are getting a false positive reading.
The RH Relative Humidity is 54.3%.

When you measure for moisture in objects you need to setup a map.
From there a baseline grid of say every square foot
You start on a interior wall or wall you consider dry to get a baseline reading, a starting point. From there move to the suspect area and map the area left to right, or right to left and from bottom up or top to bottom.

Moisture mapping is done using specific technology and instruments, such as infrared cameras, invasive moisture meters, non-invasive moisture meters, and thermo-hygrometers.

Tramex: Moisture map the water damage

1 Like

thanks a lot for explain to me

Get it your point

The MT-28 pinless moisture meter in his hand does not measure humidity. It does not include a hygrometer or a thermometer to calculate relative humidity. It is only a pinless moisture meter.


Evening, Bert.
I am going off of the manufacturers specifications.

MT28 Inductive Wood Moisture Meter Electromagnetic Wave Timber Hydrometer Tester

Sensing measurement, no harm to the survey surface. Convenient.
High -frequency electromagnetic sensing measurement
Over large detection area.
Choose different wood density.
Humidity measurement range
Wood density selection
Super LCD display, make sure the number of readings in the backlight is clear
Data maintenance function
Battery electricity indicator
Automatic shutdown function
Firelight function
Power supply by 1x9V battery (without battery)

LCD size: 2.7 inches (diagonal line)
Humidity measurement range: 5%~ 75%
Measurement error: ± 4%
Sensor size: 1.6x1.6 inches (40x40mm)
Display resolution: 0.1%
Automatic shutdown trigger: 5 minutes does not move
Storage temperature: -10 ~ 50 ° C (14 ~ 22 ° F)
Size: 150x 67x 28.5mm (5.9x 2.6x 1.1 inches)
Weight: 160 grams (5.6 ounces)
Power: 1x “9V” battery (without battery)

Call me a cynic (and maybe you’re just being a contrarion) but I wouldn’t put much stock in a product description from the manufacturer of a $30 moisture meter. Plus I don’t see anything there about RH. It is important to differentiate between humidity and moisture in a solid material.


Hi Robert. That is interesting. I guess it depends on what translation software is used. Maybe the word for moisture and humidity is similar in Chinese. The feature list on the Alibaba (Chinese Ebay) I linked to has these features, almost word for word what you posted, except the word humidity.


Inductive measurement,no harm on the measured surface. Convenient and fast.
Measurement though HF electromagnetic sensing
Super largedetection area.
different timber density at option.
Wide moisture measurement range
Wood density selection
Ultra-large LCD display ensuring clear readings with backlight.
Data hold function
Battery level indication
Auto power-off function
With flashlight function
Powered by 1x9V battery (You can choose the model with or without rechargeable battery)

If you look at the product video and read the four modes are Wall, Masonry, Hardwood, and softwood you will learn that there is no hygrometer on this instrument, and no thermometer either, so an RH reading is not happening on this device.

However by you posting your alternate translation, it does make me wonder if the OP is also using a bad translation from his native tongue and he meant to say moisture content but his translator software gave him “Humidity” instead. I’ll give him the benefit of the doubt, and now he surely knows that in English there is a big difference in the meaning of those two terms.


Moisture meters, both pinned and pinless, measure the conductivity of the underlying materials as a proxy for detecting moisture. Moisture causes conductivity in the material to rise, hence the usefulness of these devices in detecting possible moisture. However, there are tons of other things in walls and floors that can increase conductivity including nail heads, metal drywall patches, and, in this case, a metal corner bead. The pinned moisture meters are much more foolproof. However, any time you get a high reading on a moisture meter (of any type), first ask yourself is it actually moisture or something metallic (conductive) that is raising the conductivity? In this case, I presume there is nothing else pointing to moisture (e.g. stains, water damage), so likely a metal corner bead.

perfect answer. Thanks a lot