Copyright
2009, Delmhorst Instrument Co.
Page 11 of 35
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.
Subsurface test:
Drill two 1/4" holes,
3/4" apart and 1/2" to 2" deep.
Drive the masonry nails
into the bottom of the holes and make the tests as described
above. Nails must not touch sides of drilled holes.
If the meter still indicates a “dry” condition, the floor is ready for covering. Tests should
be made at several points, especially when the slab is thick (4” or more) and air
circulation is poor. Make tests only in newly drilled holes.
Eve
n readings in the “wet” range can indicate relatively low moisture content in Concrete.
For example, readings in the “28 - 35” range indicate approximately 2% to 4% moisture
content.
When evaluating a slab for readiness, always consider its age, thickness, whether the
slab is on grade or suspended, whether a vapor barrier is present and the drainage
condition of the ground.
TESTING INSULATION:
Set the meter to the Wood scale
. Remember that when used on materials other than wood,
the meter’s
PIN
mode will give relative readings only. Establish a baseline reading by taking a
reading in an area you know to be unaffected, then take a reading in the affected area and
compare the two readings.
To take a reading,
attach a 21-
E electrode with 4” insulated contact pins to the meter. Push
the contact pins through the drywall into the insulation behind it.
Press the SELECT button
and read the relative moisture level on the meter scale. The
meter displays the “relative” moisture level for two seconds.
TESTING DRYWALL
USING PIN MODE
Set the meter scale to
Drywall
To take a reading,
push the contact pins into the drywall to their full penetration, if possible.
Press the SELECT button
and read the moisture content on the meter scale. The meter
displays the %MC for two seconds.
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