CMR Moisture Control & Building Science 2 — Questions and Answers
Question 1: Which instrument is used to measure relative humidity and temperature simultaneously in the field during a mold assessment?
- Anemometer
- Thermo-hygrometer (psychrometer) (Correct answer)
- Manometer
- Particle counter
Correct answer: Thermo-hygrometer (psychrometer)
A thermo-hygrometer or psychrometer simultaneously measures ambient temperature and relative humidity, which are both critical data points for evaluating moisture-related mold risk.
Question 2: In a 'stack effect' scenario common in multi-story buildings, how does moisture move?
- Moisture moves laterally through exterior walls only
- Warm moist air rises and exits at the top while cold air infiltrates at the bottom (Correct answer)
- Cold dry air enters at the top and pushes moisture to the basement
- Moisture movement is driven solely by wind pressure
Correct answer: Warm moist air rises and exits at the top while cold air infiltrates at the bottom
The stack effect causes warm, buoyant air to rise and exit through upper floors and roof, while replacement cold air infiltrates at the lower levels, carrying moisture upward through the building in the process.
Question 3: What is the purpose of a negative air pressure containment during mold remediation from a moisture-control perspective?
- To dry out wet materials faster by moving air
- To prevent mold spores from migrating to unaffected areas and to control indoor humidity (Correct answer)
- To increase the temperature in the work area
- To reduce the need for personal protective equipment
Correct answer: To prevent mold spores from migrating to unaffected areas and to control indoor humidity
Negative air pressure containment creates an airflow into the work area, preventing spore-laden and potentially moist air from escaping into clean zones and cross-contaminating unaffected building areas.
Question 4: Efflorescence on a basement wall most directly indicates:
- Normal concrete curing byproducts with no moisture concern
- Water has been moving through the masonry, depositing salts on the surface (Correct answer)
- High radon levels behind the wall
- Incorrect paint application on the surface
Correct answer: Water has been moving through the masonry, depositing salts on the surface
Efflorescence is the white crystalline deposit left when water carrying dissolved salts migrates through masonry and evaporates at the surface, confirming active or historic water intrusion through the wall.
Question 5: A hygroscopic building material is one that:
- Repels water and dries quickly after wetting
- Absorbs and releases moisture in response to ambient humidity changes (Correct answer)
- Is immune to mold growth due to its chemical composition
- Only allows one-way moisture transmission
Correct answer: Absorbs and releases moisture in response to ambient humidity changes
Hygroscopic materials like wood, gypsum, and cellulose readily absorb water vapor from the air when humidity is high and release it when humidity drops, making them particularly susceptible to mold when sustained moisture is present.
Question 6: Which of the following best describes 'interstitial condensation' in a building assembly?
- Condensation that forms on the interior side of windows
- Condensation that occurs within a wall, floor, or ceiling cavity when warm moist air meets a cold surface (Correct answer)
- Surface moisture from cleaning products left on walls
- Rain condensation on exterior cladding
Correct answer: Condensation that occurs within a wall, floor, or ceiling cavity when warm moist air meets a cold surface
Interstitial condensation occurs when moisture-laden air penetrates into a building assembly and condenses on a cold surface within the cavity, often leading to hidden mold growth inside walls or roofs.
Question 7: After completing mold remediation, what moisture condition must be achieved in building materials before encapsulation or reconstruction begins?
- Materials must reach ambient outdoor humidity levels
- Materials must be dried to acceptable baseline moisture content levels as specified by IICRC S520 standards (Correct answer)
- Materials must be completely dry with 0% moisture content
- Materials must test negative for mold spores only, regardless of moisture level
Correct answer: Materials must be dried to acceptable baseline moisture content levels as specified by IICRC S520 standards
IICRC S520 requires that affected materials be dried to baseline (pre-loss) moisture content levels before reconstruction to prevent recurring mold growth behind new finishes.
CMR Moisture Control & Building Science 2
Which instrument is used to measure relative humidity and temperature simultaneously in the field during a mold assessment?