MRS Moisture Assessment & Detection 2 — Questions and Answers
Question 1: What does a psychrometric chart primarily help a mold remediation specialist determine?
- The species of mold present in a structure
- The relationship between temperature, humidity, and dew point (Correct answer)
- The tensile strength of building materials
- The age of a water-damaged building component
Correct answer: The relationship between temperature, humidity, and dew point
A psychrometric chart displays the thermodynamic properties of moist air, helping specialists understand how temperature and relative humidity interact to affect dew point and condensation risk.
Question 2: Which instrument measures the moisture content of air by comparing the readings of a wet-bulb and dry-bulb thermometer?
- Hygrometer
- Sling psychrometer (Correct answer)
- Pin-type moisture meter
- Borescope
Correct answer: Sling psychrometer
A sling psychrometer uses two thermometers — one with a wet wick — and the difference in their readings is used to calculate relative humidity.
Question 3: When assessing a crawl space, a specialist finds standing water and saturated soil. What is the FIRST corrective action to identify before remediation begins?
- Apply biocide to all visible mold colonies
- Identify and eliminate the source of moisture intrusion (Correct answer)
- Install a vapor barrier over the wet soil
- Remove all wood framing in contact with soil
Correct answer: Identify and eliminate the source of moisture intrusion
Source control must be established first; remediating mold without stopping moisture intrusion will result in rapid mold recurrence.
Question 4: A non-invasive moisture meter reads 22% on a wood floor. What does this reading most likely indicate?
- The wood is bone dry and requires no further assessment
- The moisture level is within acceptable range for finished wood flooring
- Elevated moisture that warrants further investigation with an invasive meter or deeper probing (Correct answer)
- The wood has reached equilibrium moisture content and is stable
Correct answer: Elevated moisture that warrants further investigation with an invasive meter or deeper probing
22% moisture in wood flooring exceeds typical equilibrium moisture content for interior wood (6–12%) and warrants further investigation to confirm the extent of moisture.
Question 5: What phenomenon explains why mold often grows on cold exterior walls near the floor in heated buildings?
- Thermal bridging causing the surface temperature to drop below dew point (Correct answer)
- High air pressure forcing moisture into wall cavities
- Insufficient insulation causing elevated surface temperatures
- Stack effect drawing dry air downward along exterior walls
Correct answer: Thermal bridging causing the surface temperature to drop below dew point
Thermal bridging allows cold exterior temperatures to lower wall surface temperatures below the indoor dew point, causing condensation and creating conditions for mold growth.
Question 6: During an assessment, a specialist uses fluorescent dye testing in a plumbing system. What is the primary purpose of this technique?
- To identify the species of mold growing near plumbing
- To trace the path and source of water leaks (Correct answer)
- To measure the pH level of moisture in building materials
- To determine the age of a plumbing leak
Correct answer: To trace the path and source of water leaks
Fluorescent dye is introduced into a plumbing system and UV light is used to trace where the dye — and thus water — is migrating, confirming leak sources.
Question 7: Which building material typically requires the LOWEST moisture content reading to support mold growth?
- Concrete block
- Fiberglass insulation
- Gypsum wallboard (drywall) (Correct answer)
- Ceramic tile
Correct answer: Gypsum wallboard (drywall)
Gypsum wallboard contains organic paper facing that can support mold growth at relatively low moisture levels, making it one of the most vulnerable common building materials.
MRS Moisture Assessment & Detection 2
What does a psychrometric chart primarily help a mold remediation specialist determine?