The Moisture Measurement Blog

October Newsletter 2015 Ligno-DuoTec BW in-situ probe RH test


October 2015,

Issue No. 15

Interesting Websites

The cure for concrete moisture and PH Ills

(see more)

Understanding, Preventing, Detecting and Correcting Moisture in Concrete Floors

(read more)

Keep in Touch:

PHONE: (800) 227-2105

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FAX:      (503) 256-3844



October Sale on all Moisture Meters

Now is a good time to buy. The sale prices are good through October 31st.

Using the Ligno-DuoTec BW moisture meter for in-situ probe measurements in concrete.

The Ligno-DuoTec BW is a dual-depth pinless meter for wood floors, bamboo, and gypsum. The meter in pinless mode also gives comparative readings of concrete and other materials (Photo 2).

The Ligno-DuoTec BW meter can be used with the RH BluePeg Probes to measure ambient conditions of air and in-situ RH probes in concrete.

Image 1: Taking an RH measurement with the Ligno-DuoTec BW. Using ASTM F2170 standard. Easy and accurate measurements can be taken with a 3 mm connector RH cable.

Image 2: Pinless readings are taken when scanning the concrete surface. A great strategy to us to find where to set your probes when taking in-situ probe readings. 

However when only using the pinless moisture meter to evaluate concrete there are some major disadvantages. Any pinless meter is limited because the measuring depth is only ¾” . Moisture below the ¾” measuring depth is not included in the pinless measurements.

If problems with high concrete moisture are present a greater measuring depth is required to detect the higher moisture levels. In most cases the moisture in a concrete floor is highest 40% down into a concrete slab.  The in-depth RH Probes are able to reach deep enough to detect hidden internal moisture in concrete slabs. Flooring failure is often caused when the internal moisture raises to the surface once the concrete slab is covered.

The following photo shows all parts necessary to perform an RH test (vacuum or shop vac is not in photo)

1 Ligno-DuoTec BW moisture meter indicating RH and Temperature measurements,

RH Cable,

RH BluePeg Probes,

Sleeves (caps not in photo)

Plus attachment to vacuum inside the hole and a

Brush to clean hole before inserting sleeve.

After all parts are on site, the number and location of the measuring points is established. Each hole is drilled with a 5/8” drill bid, cleaned and brushed out. Plus the sleeve is inserted and the cap put in place before the next hole is drilled.

Each hole is drilled with a 5/8” drill bit, cleaned and brushed out. Plus the sleeve is inserted and the cap put in place before the next hole is drilled.

The Lignomat sleeves can be pressed into the hole by using your hands. Using a wooden block or a rubber mallet makes inserting the sleeves easy. The numerous ribs on the side of the sleeve and the lip on the top of the sleeve assure a tight fit, where no air from the hole can escape once the cap is in place. 

At any time after the sleeves have been set, the RH BluePeg Probes can be inserted.

The red cap is used once the RH BluePeg Probe is inserted to mark the location of sleeves, which have the RH BluePeg Probe inside.

For a pretest the probes can be inserted within an hour of drilling the holes. RH measurements after a few hours give a good indication of the moisture range in the concrete slab.

If it is established at that time that the concrete needs more drying time, the RH probes can be removed from the holes and used for later testing.

Once the cable is connected to the meter, the READ key can be depressed and the RH value is indicated. The number on the left side of the display indicates the individual RH BluePeg serial number. This allows for easy tracking of the RH BluePeg Probes.

To obtain temperature readings, simply depress the down key and the temperature is indicated.

To remove the cable, hold the black cable-end plug in place and pull on the cable. The RH BluePeg Probe is disconnected from the cable. Cable and cable-end-plug can be removed, without removing the Rh BluePeg Probe.

If the RH BluePeg Probe should be removed, connect the cable again and pull the RH BluePeg Probe out of the sleeve.

The RH Probe can be used now for further testing.

The Ligno-Duotec BW is a great meter for floor installers and inspectors. All-important moisture testing functions for flooring installations and inspections are built-in.

A further step up is the Ligno-VersaTec,  which has all features of the Ligno-DuoTec BW plus, an external electrode can be connected for measurements in pin mode.