Delmhorst Instrument Navigator - Manual (Page 23)

Copyright

2007, Delmhorst Instrument Co.
Page 23 of 28
will move into a hygroscopic (wood) floor, or build-up pressure under a non-breathing synthetic
floor, causing delamination.
Taking a surface reading:
Drive two hardened-steel masonry nails about 3/4" apart into the finish coat of concrete floor.
Drive them about 1/8" deep so they make firm contact with the concrete and do not move when
touched.
Ø Touch the nails with the contact pins.
Ø Press the select key and read the meter. If the meter reads less than “68”, the surface
is dry. However, sub-surface tests should be made to verify if the slab is dry throughout.
Subsurface test:
Ø Drill two 1/4" holes, 3/4" apart and 1/2" to 2" deep.
Ø 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.
Even readings in the “wet” range can indicate relatively low moisture content in Concrete.
For example, readings in the “68 to 77” 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 scale for PLASTER as described in the Create/Modify a Job section on page
11.
⇒
To take a reading, attach a 21-E electrode with 4” insulated contact pins to the meter. Push
the contact pins through the Sheetrock® into the insulation behind it.
⇒
Press the SELECT button and read the moisture content on the meter scale. The meter
displays the “relative” moisture level for two seconds.