Co Drywall Contractor Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following materials is primarily used in standard drywall
panels?
A. Plywood
B. Gypsum
C. Concrete
D. Fiber cement
Rationale: Gypsum is the core material in drywall panels due to its
fire-resistant and soundproofing properties.
2. What is the typical thickness of interior residential drywall?
A. 1/4 inch
B. 1/2 inch
C. 3/4 inch
D. 1 inch
Rationale: 1/2 inch drywall is standard for most interior walls in
residential construction.
3. Which type of drywall is specifically designed for moisture-prone areas
like bathrooms?
A. Regular drywall
B. Greenboard
C. Fire-rated drywall
D. Veneer plasterboard
Rationale: Greenboard contains moisture-resistant additives, making
it suitable for damp areas.
4. When installing drywall, the sheets should be fastened perpendicular
to:
, A. Floor joists
B. Ceiling joists
C. Wall studs
D. Window frames
Rationale: Fastening perpendicular to studs provides maximum
support and reduces sagging.
5. What is the recommended spacing for drywall screws on walls?
A. 4 inches
B. 6 inches
C. 12 inches
D. 24 inches
Rationale: 12 inches on walls is standard to ensure stability without
overfastening.
6. For ceilings, drywall screws should be spaced at:
A. 12 inches
B. 8 inches
C. 16 inches
D. 24 inches
Rationale: Ceiling drywall requires closer spacing to prevent sagging.
7. Which type of drywall is typically used for fire-rated assemblies?
A. Regular drywall
B. Greenboard
C. Type X drywall
D. Veneer plasterboard
Rationale: Type X drywall contains fiberglass additives to increase
fire resistance.
8. What is the main purpose of using corner beads in drywall installation?
A. To increase insulation
B. To hide nails
C. To protect and create smooth corners
D. To prevent mold
Rationale: Corner beads provide a durable edge and smooth finish at
outside corners.
9. Which tool is commonly used to cut drywall sheets?
A. Jigsaw
B. Circular saw
C. Utility knife
, D. Reciprocating saw
Rationale: A utility knife scores and snaps drywall cleanly without
damaging the core.
10. When hanging drywall, seams should ideally be:
A. Staggered between sheets
B. Aligned in straight lines
C. Placed in the corners
D. Overlapping
Rationale: Staggering seams adds strength and reduces cracking.
11. Joint compound is primarily used for:
A. Attaching drywall to studs
B. Filling and finishing seams
C. Moisture protection
D. Soundproofing
Rationale: Joint compound fills seams, screw holes, and creates a
smooth finish for painting.
12. What is the minimum number of drywall layers required for a
one-hour fire-rated wall assembly?
A. 1
B. 2
C. 2 layers of Type X
D. 3
Rationale: Two layers of Type X drywall are typically required to meet
a one-hour fire rating.
13. What is the proper technique for applying joint tape?
A. Apply tape first, then mud
B. Embed tape in wet joint compound
C. Tape over dried mud
D. Use only nails
Rationale: Taping in wet mud ensures adhesion and prevents bubbles.
14. When sanding joint compound, what safety equipment is
recommended?
A. Gloves only
B. Dust mask or respirator
C. Earplugs
D. Safety boots
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following materials is primarily used in standard drywall
panels?
A. Plywood
B. Gypsum
C. Concrete
D. Fiber cement
Rationale: Gypsum is the core material in drywall panels due to its
fire-resistant and soundproofing properties.
2. What is the typical thickness of interior residential drywall?
A. 1/4 inch
B. 1/2 inch
C. 3/4 inch
D. 1 inch
Rationale: 1/2 inch drywall is standard for most interior walls in
residential construction.
3. Which type of drywall is specifically designed for moisture-prone areas
like bathrooms?
A. Regular drywall
B. Greenboard
C. Fire-rated drywall
D. Veneer plasterboard
Rationale: Greenboard contains moisture-resistant additives, making
it suitable for damp areas.
4. When installing drywall, the sheets should be fastened perpendicular
to:
, A. Floor joists
B. Ceiling joists
C. Wall studs
D. Window frames
Rationale: Fastening perpendicular to studs provides maximum
support and reduces sagging.
5. What is the recommended spacing for drywall screws on walls?
A. 4 inches
B. 6 inches
C. 12 inches
D. 24 inches
Rationale: 12 inches on walls is standard to ensure stability without
overfastening.
6. For ceilings, drywall screws should be spaced at:
A. 12 inches
B. 8 inches
C. 16 inches
D. 24 inches
Rationale: Ceiling drywall requires closer spacing to prevent sagging.
7. Which type of drywall is typically used for fire-rated assemblies?
A. Regular drywall
B. Greenboard
C. Type X drywall
D. Veneer plasterboard
Rationale: Type X drywall contains fiberglass additives to increase
fire resistance.
8. What is the main purpose of using corner beads in drywall installation?
A. To increase insulation
B. To hide nails
C. To protect and create smooth corners
D. To prevent mold
Rationale: Corner beads provide a durable edge and smooth finish at
outside corners.
9. Which tool is commonly used to cut drywall sheets?
A. Jigsaw
B. Circular saw
C. Utility knife
, D. Reciprocating saw
Rationale: A utility knife scores and snaps drywall cleanly without
damaging the core.
10. When hanging drywall, seams should ideally be:
A. Staggered between sheets
B. Aligned in straight lines
C. Placed in the corners
D. Overlapping
Rationale: Staggering seams adds strength and reduces cracking.
11. Joint compound is primarily used for:
A. Attaching drywall to studs
B. Filling and finishing seams
C. Moisture protection
D. Soundproofing
Rationale: Joint compound fills seams, screw holes, and creates a
smooth finish for painting.
12. What is the minimum number of drywall layers required for a
one-hour fire-rated wall assembly?
A. 1
B. 2
C. 2 layers of Type X
D. 3
Rationale: Two layers of Type X drywall are typically required to meet
a one-hour fire rating.
13. What is the proper technique for applying joint tape?
A. Apply tape first, then mud
B. Embed tape in wet joint compound
C. Tape over dried mud
D. Use only nails
Rationale: Taping in wet mud ensures adhesion and prevents bubbles.
14. When sanding joint compound, what safety equipment is
recommended?
A. Gloves only
B. Dust mask or respirator
C. Earplugs
D. Safety boots
