NCCER Interior Finishing & Drywall 1 — Questions and Answers
Question 1: What is the standard thickness of drywall used for interior walls in residential construction?
- 1/4 inch
- 3/8 inch
- 1/2 inch (Correct answer)
- 5/8 inch
Correct answer: 1/2 inch
1/2-inch drywall is the standard thickness for interior walls in most residential construction applications.
Question 2: When installing drywall on ceilings, what is the maximum recommended screw spacing in the field?
- 6 inches
- 8 inches
- 12 inches (Correct answer)
- 16 inches
Correct answer: 12 inches
Ceiling drywall screws should be spaced no more than 12 inches apart in the field to prevent sagging over time.
Question 3: What type of drywall is specifically designed for use in high-moisture areas such as bathrooms?
- Standard white-board drywall
- Type X fire-rated drywall
- Moisture-resistant drywall (green board) (Correct answer)
- Soundproofing drywall
Correct answer: Moisture-resistant drywall (green board)
Moisture-resistant drywall, commonly called green board, is manufactured to resist moisture damage in high-humidity environments.
Question 4: What is the primary purpose of Type X (fire-rated) drywall?
- To improve sound transmission class ratings between rooms
- To provide fire resistance in walls and ceilings (Correct answer)
- To add moisture resistance in kitchens
- To increase impact resistance in high-traffic hallways
Correct answer: To provide fire resistance in walls and ceilings
Type X drywall contains glass fibers in its gypsum core that slow combustion and provide code-required fire-resistance ratings.
Question 5: What is the correct technique for cutting drywall with a utility knife?
- Cut completely through both paper faces in one pass
- Score the face paper, snap the panel, then cut the back paper (Correct answer)
- Use tin snips along a scored line
- Wet the panel to soften the gypsum before cutting
Correct answer: Score the face paper, snap the panel, then cut the back paper
The score-and-snap method—scoring the face, snapping at the score, then slicing the back paper—is the standard technique requiring no power tools.
Question 6: What is the standard stud spacing used for most interior drywall installations?
- 12 inches on center
- 16 inches on center (Correct answer)
- 20 inches on center
- 24 inches on center
Correct answer: 16 inches on center
Studs spaced 16 inches on center is the standard framing interval that properly supports 1/2-inch drywall panels.
Question 7: Which orientation should drywall sheets be hung on walls for maximum structural strength?
- Vertically, with seams parallel to studs
- Horizontally, with the long edge perpendicular to studs (Correct answer)
- Diagonally at 45 degrees to the studs
- Either orientation provides equal strength
Correct answer: Horizontally, with the long edge perpendicular to studs
Horizontal installation crosses more studs with each panel, reduces vertical seams, and produces a stronger, more rigid wall assembly.
NCCER Interior Finishing & Drywall 1
What is the standard thickness of drywall used for interior walls in residential construction?