Insulation and Ventilation Flashcards

A home inspector finds vermiculite insulation in an attic. What is the most appropriate recommendation?

Answer: Recommend testing by a qualified asbestos professional due to potential contamination

Much vermiculite, especially from the Libby, Montana mine, was contaminated with asbestos; inspectors should recommend evaluation and testing by a qualified asbestos professional.

What is the primary purpose of attic baffles (rafter vents)?

Answer: To maintain an air channel from soffit vents to the attic while preventing insulation from blocking airflow

Attic baffles create an unobstructed channel between the roof deck and insulation at the eaves, ensuring blown-in or batt insulation does not block soffit vent airflow.

Which condition most clearly indicates inadequate attic ventilation during a home inspection?

Answer: Moisture stains, mold growth, or frost on attic roof sheathing

Moisture stains, mold, or frost on roof sheathing indicate that humid air is accumulating in the attic without sufficient ventilation to remove it.

What does the term 'blown-in insulation' refer to?

Answer: Loose-fill insulation installed using air-powered pneumatic equipment

Blown-in (loose-fill) insulation such as cellulose or fiberglass is installed using pneumatic equipment that blows material into attic floors or wall cavities.

What problem results when batt or blown-in insulation is compressed or disturbed from its installed position?

Answer: Reduced R-value and diminished thermal performance

Compression or disturbance reduces insulation thickness and disrupts the air pockets that provide thermal resistance, directly lowering the effective R-value.

What is the primary design purpose of a whole-house mechanical ventilation system?

Answer: To continuously exchange stale indoor air with fresh outdoor air

Whole-house ventilation systems (HRV, ERV, or exhaust-only) provide controlled fresh air exchange to dilute indoor pollutants and maintain acceptable indoor air quality.

During a crawl space inspection, an inspector finds batt insulation installed with the kraft paper vapor retarder facing downward away from the subfloor. What should be noted?

Answer: This is improper — the vapor retarder should face upward toward the warm subfloor

Insulation in a crawl space should be installed with the vapor retarder facing the warm side (toward the floor above) to prevent moisture from condensing within the insulation assembly.