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The CSDR exam has 120 questions and runs 3 hours.
These 10 free CSDR questions are organized by exam domain, so you can see how each part of the Council-certified Structural Drying Remediator blueprint is tested. Reveal the answer and explanation under each question.
Before entry into a below-grade utility vault at sea level, a technician samples the atmosphere from outside. A functioning, calibrated monitor reads 18.2% oxygen, 0% of the lower explosive limit, and no detected toxic gas. The entry plan offers a full-face respirator with P100 filters. Which instruction should the entry supervisor give?
Correct answer: D - Reject this plan; P100 filters cannot correct oxygen deficiency.
A prompt assessment of a potable-supply-line leak finds no significant contamination along the water's path. Bulk water has been extracted, but a small multilayer oak-and-plywood floor section is deeply saturated. Most exposed porous surfaces are unaffected. How should the loss be classified?
Correct answer: C - Category 1, Class 4: deeply retained moisture in low-evaporation layers
A drying log shows room air changing from 68°F and 50% relative humidity to 86°F and 28% relative humidity after an electric heater is started. The humidity ratio stays near 51 grains per pound of dry air, and the mapped material readings are unchanged. What has the lower relative humidity established?
Correct answer: A - Heating has lowered relative humidity, without demonstrating vapor removal.
Matched wood specimens of a species with a fiber saturation point near 30% are dried under controlled conditions. One dries from 45% to 35% moisture content; the other dries from 25% to 15%. Temperatures are comparable, and neither specimen develops a moisture gradient. Which dimensional response is most likely?
Correct answer: C - Greater shrinkage in the second, from loss of bound cell-wall water.
A flooring replacement is scheduled over a water-damaged concrete slab. The specified adhesive permits installation only when ASTM F2170 in-situ relative humidity is no greater than 85%. Properly performed tests at service conditions yield 87%, 89%, and 91%, although a handheld surface meter indicates 'dry.' Which conclusion belongs in the flooring-release report?
Correct answer: D - The slab has not met the adhesive's specified internal-humidity requirement.
A commercial drying chamber is at 68°F, 60% relative humidity, and 61 grains of water per pound of dry air. Outside air is at 50°F, 80% relative humidity, and 43 grains per pound. Outdoor air is clean, heating capacity is adequate, and a controlled intake/exhaust route is available. Mechanical dehumidification is already operating. For the next drying interval, the supervisor should:
Correct answer: B - Add controlled outside-air exchange to the dehumidification plan, and recheck its benefit as weather changes.
Unit X produces the larger humidity-ratio reduction, but the supervisor questions whether it removes more water. At the same inlet conditions, Unit X processes 500 kg of dry air per hour and reduces the humidity ratio from 0.012 to 0.008 kg of water per kg of dry air. Unit Y processes 800 kg of dry air per hour and reduces it from 0.012 to 0.009. Both discharge their removed water outside the chamber. Which comparison resolves the question?
Correct answer: A - Unit Y removes 2.4 kg/h; Unit X removes 2.0 kg/h.
A rotor desiccant unit delivers low-humidity process air into a drying chamber, but chamber moisture is not decreasing. Its hot reactivation exhaust is discharged into an unvented adjoining room whose door to the chamber is open. No continuing leak is found. What installation change addresses the most likely cause?
Correct answer: D - Route wet reactivation exhaust outdoors, clear of the process-air intake.
Six hours after a potable-water supply-line leak in an office, wallboard is wet but firm, with intact seams and no swelling or visible microbial growth. The source has been repaired. The uninsulated cavities are accessible for safe drying, and no other hazard or material damage has been found. Which treatment is supported by these findings?
Correct answer: B - Retain the sound wallboard, provide cavity airflow, and monitor drying to its material-specific goal.
The moisture log for a wall sole plate reads 22% on Monday, 17% on Tuesday, and 11% on Wednesday. The drying goal is 12% or less. Monday and Tuesday were measured with insulated pins at 25 mm depth; Wednesday's reading used the same corrected wood scale but penetrated only 3 mm. The technician reports that the sole plate has met the goal. What evidence is missing?
Correct answer: A - A comparable insulated-pin reading at 25 mm depth confirming the previously wet interior.
The CSDR exam also covers these domains. Drill them in the full free practice test:
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