That’s the problem with less expensive testers. Not enough range of materials.
Ceramic tile in not masonry, but is the closest choice for those offered.
Curious… was this a bathroom with a shower??
When was the last shower taken?
Get where I’m going here?
It’s like a lot of instruments we use in home inspections. You need to know what the proper settings are. You need to know how to interpret the data. Inexpensive instruments will get you inexpensive result.
I wouldn’t stake my reputation or the possibility of a lawsuit on a $39 instrument.
Pull back the carpet here and check the tack strip, if it is wood and is wet, you will be able to confirm visually. (carpet can feel dry until it is saturated)
I basically had a leak upstairs from a shower door a friend didnt close a few weeks ago. So he just left it open and 3-4 days of showers eventually resulted in water showing haha.
So I just got curious got a moisture reader and went looking not my brightest move
Different materials will react differently with the meter. For example, a high sheen hardwood, or glossy tile may reflect differently, and it will test wet.
Best way to even know if there are concerns is to test multiple areas of the tile, and see if you get any fluctuations. You have to have a base reading, and this applies to all materials tested.
Sometimes with cheaper meters, even the amount of pressure you apply when testing can affect the reflection on the back side.
Are you saying on each tile individually? Whatever the content reader showed was the same throughout that whole individual tile. If you go through the whole flooring it’s different.
The entire bathroom tile is 50-60% or above with some reaching max as the pic above showed. Maybe some times were 40-50% but it was not much lower then that.
With cheaper testers, you cant really go by the percentage that it shows, you basically just have to see if you have drastic changes. If you are saying that you are getting 40% at some areas, and max at others, then it is probably picking up elevated levels. But again, I would experiment by pushing harder on the meter and see if it changes the reading. If it does, then it is useless for that application.
However, as Jeffrey stated, this would be affected also by recent humidity or shower usage.
Also, if there was moisture under the tile, you would likely see darker grout in those areas. The grout would act like a sponge
Unless the grout was a waterproof or pre-sealed type. You can confirm this by getting the grout wet and see how it reacts.