Delmhorst Instrument Moisture Check - Manual (Page 23)

Copyright  2005, Delmhorst Instrument Co.
Page 23 of 29
If you suspect a problem take a visual inspection. Look for gaps around windows, doors, air
conditioning units, light fixtures, hose bibs, dryer vents and other areas of potential penetration.
Also look for visible signs of water damage. If you feel a problem exists, use the Moisture Check
with a # 21-E electrode. This electrode includes the #608 - (4") insulated pins or #608/001 (6”)
Insulated pins in EIFS Package.
Procedure:
⇒
Drill two 1/4" holes about ¾” apart at an upward 45° angle.
⇒
Push the # 21-E Electrode into the holes through the polystyrene and into the substrate.
⇒
Press the SELECT button and read the moisture content on the meter scale. The meter
displays the %MC for two seconds.
⇒
To add a reading to the previously stored readings, release the SELECT button if you are in
triggered mode. If you are in continuous mode, the meter will not store a new reading until
the SELECT button is pressed and released again during the reading cycle.
*If the sheathing is plywood, set the meter to the proper species if known. If the species is
unknown, use Douglas Fir. If the sheathing is gypsum material, set the species to Drywall.
USING 0-100 NUMERICAL REFERENCE SCALE (REL 0-100)
When taking a reading on hard materials such as concrete or masonry, set the meter to REL 0-
100 for a qualitative indication of the moisture level.
Make the best use of reference scale by first establishing a benchmark for the material you are
testing. Take readings in areas that you know are dry, or acceptable. Then take readings on
areas that are wet. These “dry to wet” readings can be used as reference points against which
subsequent readings are compared. Understanding the meter’s behavior on a particular material,
along with these comparative readings, your experience, and visual clues will all help determine
the overall condition. All readings should be evaluated in the light of factors such as type of paint,
type of construction, and climatic conditions.
The user-selectable alarm will sound if the displayed reading is above the alarm value.
TESTING CONCRETE SLABS FOR FLOORING APPLICATIONS
Moisture meters are an effective tool to check moisture in concrete. They can tell you where there
may be excess moisture and help determine if you need to conduct further testing.
It is important to test both the surface and mid-section of the slab, especially if the slab is on or
below grade. This will help determine if there is continuous moisture migration toward the
surface. If this condition exists, the moisture movement may be so slow that once it reaches the
surface, moisture evaporates and causes a “dry” reading when a surface test is made.
However, if a sub-surface test is made, the meter may read “wet” indicating the presence of
moisture. When the slab is covered and the upward movement of moisture continues, moisture
will move into a hygroscopic (wood) floor, or build-up pressure under a non-breathing synthetic
floor, causing delamination.