InterNACHI Insulation and Ventilation 2

Question 1

What is the primary purpose of a vapor retarder installed in a wall assembly?

Accepted Answer

To prevent moisture diffusion from warm to cold areas

Answer

A vapor retarder slows the movement of water vapor by diffusion from the warm, humid interior toward the cooler exterior where it could condense.

Question 2

Which ventilation ratio is the InterNACHI-accepted standard for attic ventilation when no vapor retarder is present in the ceiling?

Accepted Answer

1:150

Answer

Without a vapor retarder in the ceiling, the required net free ventilation area increases to 1 square foot per 150 square feet of attic floor area.

Question 3

A home inspector observes fiberglass batt insulation installed without facing in a vented crawl space floor. What is the most likely concern?

Accepted Answer

Insulation will eventually fall due to lack of support and contact loss

Answer

Unfaced batts installed between floor joists in a crawl space typically sag and fall over time, losing contact with the subfloor and greatly reducing effectiveness.

Question 4

What condition does the term 'thermal bypass' describe in an insulated building assembly?

Accepted Answer

Air movement around or through insulation reducing its effectiveness

Answer

A thermal bypass occurs when air moves through or around insulation, carrying heat with it and significantly degrading the assembly's overall thermal performance.

Question 5

Which type of insulation is most appropriate for sealing small irregular gaps around pipes and wiring penetrations through top plates?

Accepted Answer

Two-component spray polyurethane foam

Answer

Two-component spray polyurethane foam expands to fill irregular shapes and adheres to most surfaces, making it ideal for air-sealing small penetrations.

(InterNACHI) International Association of Certified Home Inspectors Practice Test

(InterNACHI) International Association of Certified Home Inspectors Practice Test

InterNACHI Insulation and Ventilation 2