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The CSMI exam has 50 questions and runs 2 hours.
These 10 free CSMI questions are organized by exam domain, so you can see how each part of the Council-certified Structural Mold Investigator blueprint is tested. Reveal the answer and explanation under each question.
A contractor labels a cool patch on an infrared image of a wall 'confirmed moisture.' The wall looks undamaged, and no material-moisture readings have been taken. Before recommending removal, the investigator should:
Correct answer: D - Check the patch with moisture measurements and a matched dry reference
Several culturable air samples yield small colony counts. A field blank, handled, transported, and analyzed with those samples without drawing air, grows the same fungal genus. How should the investigator address the blank result?
Correct answer: B - Investigate media, handling, and processing contamination before interpreting the low counts
Musty odors begin in three offices when their shared air handler starts. Offices served by another unit are unaffected. Wall and ceiling moisture readings are unremarkable, while the maintenance log records repeated condensate-drain blockages. Where should the source investigation focus first?
Correct answer: C - The shared air handler's condensate pan and adjacent porous liner
A calibrated spore-trap sampler operates at 15 L/min for 8 minutes beside a stained, musty wall. The laboratory counts 36 spores in a representative 25% of the collection deposit; no other correction applies. A contemporaneous outdoor result is already reported as 800 spores/m³. Which entry belongs in the investigation report?
Correct answer: A - 1,200 spores/m³; assess the dampness clues before attributing the elevation to an indoor source
An employee's physician diagnoses hypersensitivity pneumonitis after repeated exposure in a damp archive. The employee asks why the diagnosis does not necessarily mean a fungal lung infection. The relevant distinction is that hypersensitivity pneumonitis involves:
Correct answer: B - Immune-mediated inflammation of the lungs in response to inhaled antigens
Each cold spell brings back damp vertical strips over the steel studs in an office's exterior wall. No roof or plumbing leak is found. The room-air dew point is 54°F; the wall surface is 46°F over the studs and 65°F between them. What mechanism best explains the pattern?
Correct answer: B - Surface condensation at thermal bridges over the steel studs
A waste-line backflow originating beyond the plumbing trap wets a small carpeted area. The water appears clear and contains no visible fecal solids. Wet porous materials account for 3% of the room's combined floor, wall, and ceiling area, and low-evaporation assemblies have absorbed minimal moisture. Select the ANSI/IICRC S500-2021 classification.
Correct answer: A - Category 3 water; Class 1 water absorption and evaporation load
Fourteen hours after a potable-water supply leak, wet gypsum board remains firm, its seams are intact, and neither swelling nor mold growth is found. The leak is repaired, the uninsulated cavity is accessible for drying, and the assessment identifies no contaminating contact. Which recommendation is justified for the board?
Correct answer: D - Dry it in place and verify the affected assembly meets documented material-specific drying goals
An investigation documents dispersal of fungal material from a mold-colonized storage-room wall into an adjoining office. Laboratory analysis confirms contamination of the office air, but inspection finds no mold growing on the office's materials. Under ANSI/IICRC S520-2024, how is the office characterized?
Correct answer: C - Condition 2: analytically confirmed contamination dispersed from an actual-growth source
A 3,000 ft³ mold-remediation enclosure must meet a project-specified minimum of 6 HEPA-filtered exhaust air changes per hour and maintain inward airflow. Its only exhaust unit is rated at 600 cfm, but measured installed airflow is 250 cfm. Barriers are intact; pressure is -5 Pa relative to the corridor, and inward airflow is verified. What adjustment is needed?
Correct answer: A - Increase actual filtered exhaust to at least 300 cfm while maintaining inward airflow
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