When taking moisture readings, it is important to choose the best meter for the material, establish a drying standard and check moisture levels. Follow this process to accurately take moisture readings.
1. Choose the best meter for the material
Where possible, penetrating meters (meters that use pins or probes to "poke into" the material) are always the most reliable. However, these will create holes in the material. If the material could otherwise be saved, be sure to use a non-penetrating meter to prevent unnecessary damages.
Materials to use a penetrating meter on:
- Wood framing
- Carpet and pad
- Wood subfloor
- Batt insulation (in Category 1 water damage situations, where drying the insulation is feasible.)
- Hardwood flooring, when heavy saturation is present. (Note: A hammer probe will be needed in order to get far enough into the wood to get an accurate reading. Always chose a spot where you can hide the pin holes in the dark grain of the wood. Be sure to communicate this to the adjuster or insurance carrier, as this will require a wood floor refinishing in order to repair. )
Materials to use a non-penetrating meter on:
- Drywall
- Plaster
- Vinyl
- Ceramic tile
- Concrete
- Cabinetry
- Hardwood flooring with minimal saturation
Note: Some situations require additional considerations. For example, water trapped behind cabinetry may require the use of long probes or even large metal screws. Always consult with an ASD certified drying technician before attempting to monitor complex drying situations.
2. Establish the drying standard (AKA Drying Goal, Equilibrium Moisture Content or EMC)
Once you have determined what materials were likely affected by the water damage, locate an area of that same material elsewhere in the home, where the water damage was not present. Check this material with your moisture meter in a few spots and record the reading. This will be your drying goal. (This can also be referred to as the Equilibrium Moisture Content or EMC).
Once the wet materials have reached the same level of moisture as the materials that were not affected, you have reached your drying goal and equipment can be removed.
Note: The IICRC S500 Standard for Professional Water Damage Restoration states that a reading within 4 points of the drying goal is considered to be within the margin of error and can be considered dry.
3. Check moisture levels with a penetrating moisture meter
Using a penetrating moisture meter, push the pins fully into the affected material. Record the reading that you see. You will want to check the moisture level at several points along the affected material, to prevent the possibility of outlier data. On walls, be sure to check the same position at various heights, to validate if the water has wicked up the wall.
Tips:
- Always chose an inconspicuous place to take your readings, whenever possible. Be upfront with the customer and adjuster that this process is necessary and will require some degree of repairs (spackle, paint, wood putty, etc.) in order to return the material to pre-loss condition, due to the damaging nature of the penetrating pins and probes on a penetrating moisture meter.
- Always return to the exact same spots when monitoring the drying progress.
- The language and terminology you use is important. All materials have some degree of moisture in them, even if they are not wet. Avoid using the term "percentage" when describing a moisture reading. A meter might show that saturated drywall reads "99" or "100" on your meter. These materials are not 99-100% moisture (that would be a glass of water.) Instead, use the term "points."
- For example: "The affected walls are currently reading at 99 points. The drywall in the unaffected areas of the home is reading at 14 points. We will consider the affected drywall to be at the normal level of moisture when it reaches a level of 14 points."
4. Check levels with a non-penetrating moisture meter
Using a non-penetrating moisture meter, hold the sensor up against the affected material and record the reading that you see. As with a penetrating meter, you will want to check the moisture level at several points along the affected material, to prevent the possibility of outlier data. On walls, be sure to check the same position at various heights, to validate if the water has wicked up the wall.
Tips:
- Non-penetrating moisture meters are especially susceptible to false positives. This is especially true in cases where metal is hidden behind the material, such as drywall screws, metal framing (especially common in commercial buildings), protective plates over plumbing and electrical runs and metal corner beads. False positives can give you the impression that a material is excessively wet when it is in fact dry. Always check a variety of areas for the same material in question, to avoid a false positive from affecting your drying decisions.
- Concrete and ceramic tile are especially challenging, as even dry materials will appear to show high levels of moisture. The best way to counter this is to scan a large portion of the material in question and look for areas with inconsistently higher levels of moisture. This will often indicate true moisture inside the material.
