CHI Insulation & Ventilation Inspection 2 — Questions and Answers
Question 1: What is the primary function of soffit vents in an attic ventilation system?
- Allow hot air to escape at the ridge
- Provide cool intake air at the lower roof edge (Correct answer)
- Prevent moisture from entering the attic
- Support insulation in the rafter bays
Correct answer: Provide cool intake air at the lower roof edge
Soffit vents serve as the intake air source at the lowest point of the roof, allowing cool fresh air to enter and push hot, moist air out through ridge or gable vents higher in the attic.
Question 2: Which insulation material provides the highest R-value per inch of thickness?
- Standard fiberglass batt
- Open-cell spray foam
- Closed-cell spray foam (Correct answer)
- Blown-in cellulose
Correct answer: Closed-cell spray foam
Closed-cell spray polyurethane foam provides approximately R-6 to R-7 per inch, significantly higher than other common residential insulation materials.
Question 3: What roof-related condition commonly results from inadequate attic ventilation combined with excessive heat loss through the ceiling in cold climates?
- Thermal bridging
- Ice dams (Correct answer)
- Interstitial condensation
- Efflorescence
Correct answer: Ice dams
Ice dams form when heat escaping through a poorly ventilated attic melts snow on the roof surface, which then refreezes at the cold eave and can force water under shingles causing interior damage.
Question 4: When installing faced fiberglass batt insulation in exterior wall cavities in a cold climate, where should the vapor retarder facing be oriented?
- Toward the exterior sheathing
- Toward the warm-in-winter (interior) side of the wall (Correct answer)
- It can face either direction equally
- The facing should be removed before installation
Correct answer: Toward the warm-in-winter (interior) side of the wall
The vapor retarder facing must be installed on the warm-in-winter side (interior) to prevent moisture-laden indoor air from diffusing into the wall assembly where it can condense on cold surfaces.
Question 5: What type of ventilation relies solely on natural forces such as temperature differences and wind pressure to move air, without any mechanical equipment?
- Mechanical ventilation
- Exhaust-only ventilation
- Natural ventilation (Correct answer)
- Energy recovery ventilation
Correct answer: Natural ventilation
Natural ventilation uses buoyancy (stack effect) and wind pressure differentials to move air through openings in the building envelope without any fans or powered equipment.
Question 6: During a crawl space inspection, which observation should a home inspector flag as a deficiency requiring correction?
- Insulation installed with vapor barrier facing up toward the floor joists
- Evidence of moisture staining or mold on the insulation and framing (Correct answer)
- Ground cover vapor barrier fully covering the soil surface
- Insulation R-value meeting or exceeding local code requirements
Correct answer: Evidence of moisture staining or mold on the insulation and framing
Moisture staining or mold on crawl space insulation or wood framing indicates water intrusion or inadequate vapor control that can lead to structural deterioration and poor indoor air quality.
Question 7: What is the primary concern when cellulose insulation becomes saturated with water due to a leak or flooding?
- It immediately ignites due to combustion of its paper fibers
- It compresses, promotes mold growth, and retains moisture causing long-term structural damage (Correct answer)
- It releases toxic off-gases into the living space
- It loses its fire-retardant treatment and becomes a code violation
Correct answer: It compresses, promotes mold growth, and retains moisture causing long-term structural damage
Wet cellulose compresses significantly, losing R-value permanently, and retains moisture that promotes mold growth and wood rot in surrounding structural members.
CHI Insulation & Ventilation Inspection 2
What is the primary function of soffit vents in an attic ventilation system?