This is going to get a bit complicated: It concerns basement walls in a single-family house and whether they really have a moisture problem. The house is currently unoccupied and unheated (room temperature 20°C (68°F)). For the measurements, I bought a device on Amazon with an active electrode that shows values from 0 to 100 and is very sensitive.
After changing the rainwater drainage around the house, I carried out moisture measurements over several weeks, always at exactly the same measurement points. When taking multiple measurements at one point, the result varies by about +/-3. Therefore, I calculated an average value across all measurement points for each day and then an overall average for the room to compare the overall situation as precisely as possible.
Within one month, this average value across all points has dropped by 5.4, from 31.8 to 26.4. Since the device readings range from 0 to 100 (measurement levels), you could say that wall moisture decreased by 5.4%, or if the initial value of 31.8 equals 100%, a relative decrease of -17.0%.
However, it is unclear whether the walls still have a moisture problem or how to interpret the measurement results. I measured both an interior wall and an exterior wall in the house, 1.5 floors above (living room), and was surprised that the difference is not that great. Moreover, the air in the living room is certainly warmer and drier than in the basement, so I had expected larger differences.
Before sharing the measurements, two notes: the basement walls are made of sand-lime brick (probably due to load-bearing requirements), while the upper floors have brick walls. In the basement, measurements were taken at 0.30 m (1 foot) and 1.30 m (4 feet 3 inches) above the floor. At 1.30 m, the readings are always significantly lower (by 7–14 points) than at 0.30 m. I suspect this is normal.
Measured average values:
Basement...................: 26.4
Living room...............: 15.0
That is only a difference of 11.4 measurement points. According to the device manual, dry is 0–24, medium 25–50, and wet 51–100.
My question to the experts here is:
Is there still a moisture problem?
Since the plaster in the basement needs to be replaced, are there recommendations for specific plaster materials?
Thank you very much for your answers.
After changing the rainwater drainage around the house, I carried out moisture measurements over several weeks, always at exactly the same measurement points. When taking multiple measurements at one point, the result varies by about +/-3. Therefore, I calculated an average value across all measurement points for each day and then an overall average for the room to compare the overall situation as precisely as possible.
Within one month, this average value across all points has dropped by 5.4, from 31.8 to 26.4. Since the device readings range from 0 to 100 (measurement levels), you could say that wall moisture decreased by 5.4%, or if the initial value of 31.8 equals 100%, a relative decrease of -17.0%.
However, it is unclear whether the walls still have a moisture problem or how to interpret the measurement results. I measured both an interior wall and an exterior wall in the house, 1.5 floors above (living room), and was surprised that the difference is not that great. Moreover, the air in the living room is certainly warmer and drier than in the basement, so I had expected larger differences.
Before sharing the measurements, two notes: the basement walls are made of sand-lime brick (probably due to load-bearing requirements), while the upper floors have brick walls. In the basement, measurements were taken at 0.30 m (1 foot) and 1.30 m (4 feet 3 inches) above the floor. At 1.30 m, the readings are always significantly lower (by 7–14 points) than at 0.30 m. I suspect this is normal.
Measured average values:
Basement...................: 26.4
Living room...............: 15.0
That is only a difference of 11.4 measurement points. According to the device manual, dry is 0–24, medium 25–50, and wet 51–100.
My question to the experts here is:
Is there still a moisture problem?
Since the plaster in the basement needs to be replaced, are there recommendations for specific plaster materials?
Thank you very much for your answers.
-AK-18- schrieb:
After changing the rainwater drainage around the house -AK-18- schrieb:
it is now unclear whether the walls still have a moisture problem -AK-18- schrieb:
Is there still a moisture issue at all? So far, we still don’t know what kind of moisture problem you had in the house. Was there rainwater intrusion? A flood three years ago?
Did you buy a hygrometer to measure the air humidity, or did you get a moisture meter for measuring the walls? It sounds more like the former 😉
-AK-18- schrieb:
That’s only a difference of 11.4 measurement levels. According to the device manual, Dry is 0-24, Medium 25-50, and Wet 51-100. If the manual gives you reference values, you don’t necessarily need expert knowledge, but you should still be able to assess the overall situation on site.
Moisture cannot be judged by measurements alone.
A forum like this cannot tell you from a distance whether your walls still have residual moisture. There are other factors to consider beyond the readings.
ypg schrieb:
what kind of moisture problem did you have in the house?There was some mold on the walls near the baseboards and moisture stains above them. A questionable company carried out moisture measurements and found the walls to be highly damp. However, no measurement report was provided initially. After requesting it, I noticed that the two technicians didn’t record any values during the on-site inspection. This naturally raised doubts about the results, especially since the walls in the living room (see values in the question above) were measured as "dry."
The manual only includes a table with values for wood, gypsum (mineral), and cement-based materials. But what about calcium silicate blocks and bricks?
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