Care must be taken interpreting the readings when using these types of meters contaminants within plasterwork can be electrically conductive.
Wall moisture meter readings.
If there are quite small amounts of moisture in a wall of dense plaster or brick then a meter will probably indicate over 20 or so and this will be in the red zone or beeps and squeeks may happen.
In many cases a moisture meter s reference scale will range from 0 100 but that reading should not be confused with a percentage.
For example say you have two different moisture meters.
Moisture meters are used to measure the percentage of water in a given piece of wood and are most useful when the percentage of moisture ranges from 5 to no more than 30.
When the moisture content is around 30 wood reaches its fiber saturation point or fsp.
When used on the timber the readings recorded are moisture content relative.
One meter might have a reference mode setting that displays moisture values from 0 300 while the other one goes from 0 100.
The bd 2100 s drywall moisture meter readings are accurate in gypsum to moisture content percentages as low as 0 2 and as high as 50.
In the wood scale the meter can detect moisture accurately over a range of 6 mc to 40 mc.
I have seen drywall in a garage show 15 with a pin type meter on a hot summer day with high rh and the high reading was due to the high humidity and nothing more.
As readings exceed 20 wme remedial works are deemed necessary to this area.
Other types of meters are available from ones that use electromagnetic waves to detect moisture under the wall.
The readings obtained using these meters cannot be relied upon on their own to diagnose rising and penetrating damp.
The speedy chemical moisture meter gives a quantitative reading of the total moisture content in masonry.
Moisture meter readings i would say that 6 is fairly normal in an occupied home.
While it might be tempting to think of readings on the 0 100 reference scale meter as percent values they are not.
Some meters use a 0 300 reference scale so readings taken on a reference scale often do not.
The unit provides a moisture level range of 5 percent to 50 percent in wood and 1 5 percent to 33 percent in building materials and offers an audible indication of moisture level and storage of moisture level readings.