Delmhorst Instrument Accuscan - Manual (Page 8)

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hSurface moisture increases the readings. Depending on the
application, we recommend using a Delmhorst pin meter
with insulated pins to determine if a normal gradient (wet
core to drier outer surface) is present or if surface
moisture has just soaked into the board.
USING THE 0-100
REFERENCE SCALE:
read the
section on page 3 again before
proceeding
Testing Concrete Slabs for
Flooring Applications
hMoisture 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.
hFor best results, we recommend using ACCUSCAN in
conjunction with a pin type meter for concrete flooring
applications. ACCUSCAN will allow you to scan a large
area quickly and easily, while the pin type meter will allow
you to conduct a sub surface test.
hIf you have determined that you must use a pin-type
moisture meter, 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.
hIf the meter still indicates “dry” reading in the green
section of the scale, the floor is ready for covering.
Perform tests in several areas, especially when the slab is
thick and air circulation is poor.
hIf more precise testing is required, use the Delmhorst Total
Check 3-in-1 meter to measure the % relative humidity in
a slab, in accordance with ASTM standard F2170.