We arrived on site at about 11:00 am. This damage was caused by an angry ex-wife who placed the water hose inside the basement window and it ran for hours. The basement was fully finished and was 4000 sq ft. The dry time was 18 hours, and all carpets and base were saved! There was only a minor drywall patch. The pad replacement was due to the moisture barrier.

The home owner was very happy. His loss was completely restored in just four days. The insurance company was as extremely happy about the money we saved them as the timely completion of the job.

Getting the Most and the Most Accurate Information from Your Meters

One can not properly restore a water damage loss without know the answers to basics questions including - What materials are wet? How wet are they? Are the wet materials getting dry? What is dry? The meters needed to correctly answer these questions can cost upwards of $1,000. It is obvious that restorers should know how to get the most out of their meters including the most accurate information.

The three basic tools used by a restorer to learn what is wet and what is dry are the invasive or pin type meter, the non-invasive meter and the thermohygrometer. These may be separate instruments or multiple functions package in one unit. We'll examine each in turn.

Invasive and Non-Invasive Meters

The pin type meter is a good starting point. They operate by detecting changes in electrical conductivity. Pins or probes are inserted into the material being tested. The resistance of the material between the two pins is read and displayed by the meter. The resistance is effected by moisture content.

The non-invasive meter uses capacitance to detect moisture. The sensor which makes contact with the material being tested sends a radio frequency signal into the material being tested. Depending on the material being tested and the meter being used, the signal may measure from depths from ¼" to slightly over 1".

The advantage of a non-invasive meter is that it does not damage the surface being tested and can be quickly moved from one point to another. This allows the restorer to quickly scan a large surface such as a wall for moisture.

Scott Warrington, Technical Support Specialist for Bridgepoint Systems, notes that pinless meters can be effected by surface moisture and that they will display an average moisture content from the surface to the depth the signal reaches. Pin type meters can read from just the tip of the probe and thus show the precise moisture content at any given depth, even well beyond the range of a meter using a radio signal.

Meters are available that are calibrated to provide accurate readings on a variety of surfaces including wood, concrete, dry wall and so forth. Micah Richardson of Express Distributing of Billings Montana favors one meter actually can be switched to read any of 69 different species of wood. Most meters can be trusted to provide accurate readings for pine construction lumber.

Qualitative VS. Quantitative Scales

Measurements for wood typically display a percentage of moisture content. Scales for other materials are usually relative and provide a qualitative reading. The scale may range from 1 to 100 or 1 to 300. A reading on the lower end of a relative scale is drier than a reading on the high end of the scale but the numbers do not directly correspond to moisture content. At least one meter provides a calibrated scale that shows a quantitative reading for drywall. According to Paul Laurenzi, Vice President of Sales and Marketing for Delmhorst Instrument company, drywall is an excellent location for mold to flourish. Having a quantitative measurement of the moisture content allows the restorer to make better informed decisions regarding remediation.

Temperature of Materials Effects Accuracy of Readings

More and more restorers are seeing the benefits of using directed heat drying systems. That means that the temperatures of the materials they are checking can be significantly higher than common room temperatures. Dave Hanks of TES Drying Systems says that "Most meters are calibrated at about 70OF. As a general rule of thumb a variation of 20O or less is not significant. In other words, if the material you're measuring is between 50OF and 90OF, no correction is necessary." As temperature increases, electrical resistance decreases and the indicated moisture content rises. It is then necessary to adjust or correct the reading to get the true moisture content. With most meters, this requires consulting a chart. One series of meters is unique in its ability to automatically make temperature corrections.

Jeremy Reets, instructor for Reets Drying Academy, provides an example of this. "Each meter has a different chart or formula for correcting the moisture reading. For example, if a certain meter that gives you a reading of 15% on a 100OF material, the actual moisture content is 12% when adjusted for temperature. I like meters that have the ability to adjust this reading for me, saving me or my technicians a lot of time and making my moisture readings much more accurate."

Tom Rochenski of Extech notes that some meters offer a built in Infrared Thermometer for instant accurate readings of the high surface temperatures of the building materials. His advice for the best way to get an accurate understanding of how drying is progressing - "The best way to get an accurate reading is to first take a measurement of an unaffected area to get a starting point. Once you have established the starting point or a 'dry standard' you can use the meter in the affected area to gauge the drying process. Once the unaffected and affected areas are similar in readings then it would be fairly safe to assume that the test area is dry."

Even among the same make and model there can be variations from one meter to another, so it is wise to use the same instrument as you take and record daily readings on a job site.

Accessories

The proper accessories can make your pin-type meter useful for many additional applications such as checking insulation behind dry wall, sub floors, behind baseboard and trim, in ceilings and even books and documents.

The Slide Hammer or Hammer Probe has pins that read only from the non-insulated tips. This allows the restorer to get readings at various depths as you penetrate through floorings, walls or concrete. Ron Colling, National Director of Restoration Sales for Interlink Supply, suggests "... using a hammer probe from the under side of a wood floor to avoid repairs that may or may not be acceptable to the client. Think about having someone pounding holes into YOUR wood floor."

The Deep Wall Probe has 4" long insulated pins similar to the hammer probe. It is an excellent tool for checking stucco clad structures.

A Blade Electrode features two 5" long blades bent at an angle and coated with Teflon so the reading is made only at the tips. This is useful when looking for moisture behind trim or base molding. It is also a great tool to check for moisture in books and documents.

An accessory called a Hygrostick is available for certain meters that enables one to check the relative humidity in a concrete slab. This information is extremely important to floor covering inspectors or those involved with installing floor coverings over concrete. Moisture emissions from concrete are a common reason for installations to fail. Being able to explain or prevent these failures is very helpful.

Thermo-Hygrometers

Thermo-Hygrometers detect and recording temperature and relative humidity. These numbers are used to determine if proper drying conditions exist and to chart the progress of the drying job. These numbers can be used to calculate GPP (grains per pound), dew point and vapor pressure. Collings notes that "This can be done with a separate chart or calculator, but the restorer can save much computation time by using a meter that displays those readings directly. This can also eliminate errors in calculations."

Of course accuracy is important, but there is another comparison that should also be made when selecting a thermo-hygrometer. Water damage technicians often make dozens of readings per day. The time required for the instrument to display an accurate reading, the response time or settling rate, may be a little as several seconds or a long as a few minutes. Considering the labor value of this time multiplied by the number of readings per day, week and month makes it obvious that spending a bit extra for the right tools pays off quickly.

To view the complete calendar of events, visit us online at
http://www.tesdryingsystem.com/events.html

You may also contact the tes hotline at (800) 948-1754.