According to astm f2170 when drying concrete slabs have lower moisture levels near the surface and higher levels towards the bottom of the slab.
Measuring moisture content in concrete walls.
When testing the moisture content in non wood materials such as concrete a relative scale of 0 to 100 is often used where 0 is bone dry and 100 is saturated.
Look at the wall surface carefully.
How concrete hardens and dries concrete is manufactured by mixing cement aggregates such as sand and gravel and water.
To test for moisture inside the walls start with manual tests and proceed to moisture meters.
Moisture meters include visual led indicators related to the percent reading on the scale for dry moderate and saturated or wet readings.
Structural and safety hazards such as mold rot and decay are all potential consequences of elevated moisture levels in these materials.
Under this method you ll use a thermo hygrometer with in situ probes along with a series of prepared holes to get readings of relative humidity deep in the concrete slab.
Often more than one method is used to get an accurate reading of actual moisture content.
Additionally some meters also offer a third scale for readings of gypsum.
You see the cacl test and most other concrete moisture testing procedures employ methods such as the plastic sheet application only measure moisture escaping from the surface of the concrete slab.
In 2016 the society for protective coatings sspc expects to publish a new guidance document field methods for the determination of moisture in concrete and masonry walls and ceilings that will describe the types of instruments used for determining moisture content of walls prior to painting including recommended test frequencies.
Therefore measuring rh levels at 40 depth of the slab 20 depth if drying on two sides is more representative of the overall humidity conditions of the concrete.
There are three standard methods for measuring concrete moisture.
In the wood scale the meter can detect moisture accurately over a range of 6 mc to 40 mc.
These scale readings can range from 0 2 to 50 moisture content.
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.
A moisture meter is a device designed to measure the percent of moisture content of various building materials such as roofing siding insulation drywall plaster wood tile fiberglass and concrete.
Check for surface discoloration such as yellowing material.
A separate reference scale setting can be used for getting qualitative readings of moisture in other wall materials like plaster.
This is a relative scale.
The test is performed by sealing an insulated box to the concrete and measur ing the relative humidity inside the box with a calibrated capacitance based humidi ty gauge.
When measuring moisture in concrete the best and most reliable method is to use the astm f 2170 testing method.
