InterNACHI Interior Components and Finishes 4 — Questions and Answers
Question 1: Which interior finish material is most commonly used as a tile backer in wet areas and is resistant to moisture damage?
- Standard drywall (gypsum board)
- Cement board (cementitious backer unit) (Correct answer)
- Oriented strand board (OSB)
- Plywood sheathing
Correct answer: Cement board (cementitious backer unit)
Cement board (cementitious backer unit) is the preferred tile substrate in wet areas because it does not swell, deteriorate, or support mold growth when exposed to moisture.
Question 2: What defect is indicated when a wood floor shows cupping — edges higher than the center of each board?
- The floor was installed during low humidity and has since expanded
- Moisture is present on the underside of the flooring, causing the bottom to expand more than the top (Correct answer)
- The floor finish has caused the wood to swell from the top surface
- Excessive foot traffic has compressed the center of each board
Correct answer: Moisture is present on the underside of the flooring, causing the bottom to expand more than the top
Cupping in hardwood flooring is caused by higher moisture content on the bottom of the boards than the top, causing the bottom to expand and the edges to lift.
Question 3: During an inspection, a home's interior doors do not latch properly and several stick in their frames. The house is 40 years old. What is the most important distinction an inspector must make?
- Whether the doors are hollow-core or solid-core
- Whether the cause is normal settling/humidity or active structural movement (Correct answer)
- Whether the door hardware is original or has been replaced
- Whether the doors are interior or exterior grade
Correct answer: Whether the cause is normal settling/humidity or active structural movement
The inspector must determine whether sticking doors reflect benign seasonal swelling or past settling versus active, ongoing structural movement that requires further evaluation.
Question 4: A home inspector observes popcorn (acoustical) ceiling texture applied prior to 1980. What additional concern should be noted?
- The texture may hide water damage
- The texture may contain asbestos and should be tested before disturbance (Correct answer)
- The texture reduces room acoustics significantly
- The texture is a fire hazard due to its porous nature
Correct answer: The texture may contain asbestos and should be tested before disturbance
Popcorn ceiling textures applied before approximately 1978–1980 may contain asbestos, which poses a health hazard if disturbed; testing is recommended prior to any renovation.
Question 5: What is the recommended clearance between the bottom of an interior door and a finished floor to allow adequate air circulation for HVAC return air?
- No clearance is required for interior doors
- Approximately ½ to ¾ inch (Correct answer)
- At least 2 inches
- Exactly 1/8 inch to prevent drafts
Correct answer: Approximately ½ to ¾ inch
An undercut of approximately ½ to ¾ inch beneath interior doors allows return air to circulate back to the HVAC system when supply vents are in individual rooms.
Question 6: An inspector finds that a basement has been finished with framing and drywall directly against the exterior concrete walls with no insulation or air gap. What primary problem does this create?
- It reduces the structural integrity of the concrete wall
- It promotes condensation and mold on the cold concrete behind the drywall (Correct answer)
- It prevents future waterproofing treatments from being applied
- It violates fire separation requirements between basement and living space
Correct answer: It promotes condensation and mold on the cold concrete behind the drywall
Framing drywall directly against cold concrete without insulation or an air gap allows warm interior air to condense on the cold concrete, promoting mold growth behind the finish wall.
Question 7: Which of the following stair defects represents the most significant trip-and-fall hazard according to home inspection standards?
- Inconsistent riser heights varying by more than 3/8 inch (Correct answer)
- A slightly worn carpet runner on the treads
- Paint peeling on the stair stringers
- A handrail that is slightly higher than 38 inches
Correct answer: Inconsistent riser heights varying by more than 3/8 inch
Inconsistent riser heights exceeding 3/8 inch are a leading cause of stair falls because the body's muscle memory is disrupted mid-stair, causing missteps.
InterNACHI Interior Components and Finishes 4
Which interior finish material is most commonly used as a tile backer in wet areas and is resistant to moisture damage?