CMI CMI Advanced Diagnostic Methods 1 — Questions and Answers
Question 1: What does a thermal imaging camera detect during a home inspection that a standard visual inspection cannot?
- Structural cracks behind drywall
- Temperature differentials that may indicate moisture intrusion, insulation gaps, or electrical hot spots (Correct answer)
- The exact age of electrical wiring
- Carbon monoxide concentrations in the air
Correct answer: Temperature differentials that may indicate moisture intrusion, insulation gaps, or electrical hot spots
Infrared cameras detect surface temperature variations, which can reveal hidden moisture, missing insulation, and overloaded electrical components invisible to the naked eye.
Question 2: When using a moisture meter during a CMI inspection, a reading above what percentage in wood framing typically indicates a concern requiring further investigation?
- 5%
- 10%
- 19% (Correct answer)
- 30%
Correct answer: 19%
Wood moisture content above 19% creates conditions favorable for wood decay fungi and is the threshold that triggers further investigation or remediation recommendations.
Question 3: A CMI conducting a blower door test would use the results primarily to assess which building characteristic?
- Structural load-bearing capacity
- Building air leakage and envelope tightness (Correct answer)
- HVAC system capacity
- Foundation settling rates
Correct answer: Building air leakage and envelope tightness
A blower door test depressurizes the building to measure air changes per hour (ACH), revealing the overall airtightness of the building envelope.
Question 4: Which symptom observed during a CMI's roof inspection most strongly suggests active moisture intrusion into the attic?
- Uniform granule loss on asphalt shingles
- Staining on rafters or sheathing combined with elevated moisture meter readings (Correct answer)
- Moss growth on north-facing slopes
- Minor flashing rust on a flat roof
Correct answer: Staining on rafters or sheathing combined with elevated moisture meter readings
Staining combined with elevated moisture readings provides direct evidence of current or recent water entry, distinguishing active intrusion from old staining.
Question 5: A CMI inspecting a slab foundation observes diagonal cracking at window and door corners. This pattern most likely indicates which condition?
- Normal concrete shrinkage during curing
- Differential settlement causing stress concentration at structural openings (Correct answer)
- Thermal expansion from seasonal temperature changes
- Overloading from heavy furniture placement
Correct answer: Differential settlement causing stress concentration at structural openings
Diagonal stair-step or diagonal cracks at openings are classic signs of differential settlement, where one area of the foundation moves more than an adjacent area.
Question 6: When inspecting a gas-fired forced air furnace, which finding requires the CMI to recommend immediate discontinuation of use?
- Minor surface rust on the heat exchanger exterior
- A cracked heat exchanger confirmed by combustion spillage test (Correct answer)
- Filter that has not been replaced in 3 months
- Thermostat that overshots the set temperature by 2°F
Correct answer: A cracked heat exchanger confirmed by combustion spillage test
A cracked heat exchanger allows combustion gases including carbon monoxide to mix with supply air and distribute through the home, posing an immediate life-safety hazard.
CMI CMI Advanced Diagnostic Methods 1
What does a thermal imaging camera detect during a home inspection that a standard visual inspection cannot?