[Arizona CR-10 Drywall Contractor Exam] COMPLETE EXAM
QUESTIONS AND VERIFIED ANSWERS | 2026–2027 LATEST
UPDATE | GUARANTEED PASS | DETAILED RATIONALES |
FULL STUDY GUIDE | EXAM PREP | PRACTICE TEST |
CERTIFICATION PREPARATION
1. A project specification calls for a wall assembly to achieve a 2-hour fire-resistance rating. Which
type of gypsum board is the most appropriate choice for the base layer?
A. 1/2-inch regular gypsum board
B. 5/8-inch Type X gypsum board
C. 1/2-inch moisture-resistant gypsum board
D. 1/4-inch gypsum board
Correct Answer: B. 5/8-inch Type X gypsum board
Rationale: Type X gypsum board is specially manufactured with non-combustible fibers, typically
fiberglass, to enhance its fire-resistive properties. It is the standard material used in fire-rated
assemblies to achieve ratings of 1 hour or more. Regular gypsum board lacks these additives and will
not provide the same level of protection .
2. When installing drywall over wood studs, which fastener provides the most secure and
consistent grip?
A. 1-1/4-inch coarse-thread drywall screws
B. 1-inch fine-thread drywall screws
C. 4d box nails
D. 1-1/2-inch drywall nails
Correct Answer: A. 1-1/4-inch coarse-thread drywall screws
Rationale: Coarse-thread drywall screws are specifically designed for attachment to wood framing.
The deep threads bite into the wood fibers, providing superior holding power compared to nails or
fine-thread screws . Fine-thread screws are intended for metal studs.
3. According to the International Building Code (IBC), what is the primary purpose of fire-blocking
within a wall assembly?
A. To provide additional insulation
B. To improve the sound transmission class (STC)
C. To prevent the vertical spread of fire and smoke within concealed spaces
D. To serve as a nailing base for trim
Correct Answer: C. To prevent the vertical spread of fire and smoke within concealed spaces
,Rationale: The IBC requires fire-blocking to cut off concealed draft openings, such as the cavities
between studs. This prevents fire from traveling vertically within the wall, slowing the spread of
flames and smoke through the building .
4. A superintendent on a commercial job site notices that a layer of frost has formed on the
gypsum board stored outside. What is the most appropriate course of action?
A. Proceed with installation as planned.
B. Move the boards inside and allow them to thaw completely before installation.
C. Wipe the frost off the boards and install them immediately.
D. Discard the boards as they are now structurally compromised.
Correct Answer: B. Move the boards inside and allow them to thaw completely before installation.
Rationale: Installing frost-laden or frozen gypsum board can lead to dimensional instability as the
water within the material thaws and evaporates, causing board movement, fastener pops, and joint
cracking. The boards must be allowed to warm up to the ambient temperature of the space where
they will be installed before the finishing process begins .
5. An acoustical ceiling grid system is being installed. What is the primary function of the "main
runner" or "main tee"?
A. To hold the tile edge in place
B. To be the primary load-carrying member supported by hanger wires
C. To connect the grid to the wall angle
D. To provide a decorative finish to the ceiling
Correct Answer: B. To be the primary load-carrying member supported by hanger wires
Rationale: The main runners are the heavy-gauge structural members that run the length of the
ceiling and are directly suspended from the structure above. All other components, such as cross tees,
are attached to the main runners, which bear the main load of the ceiling system .
6. Which of the following best describes the process of "back-butting" a drywall joint?
A. Applying a second layer of tape over a finished joint
B. Cutting a relief groove into the back of a board to prevent the edges from touching
C. Staggering the seams on the opposite side of a stud wall
D. Creating a V-groove on the face of the board for a decorative finish
Correct Answer: B. Cutting a relief groove into the back of a board to prevent the edges from
touching
Rationale: Back-butting is a technique used on drywall ends that are not tapered. A groove is cut or
scraped into the back of the board at the joint, allowing the thick, square edges to come together
without touching or "riding" over each other. This ensures a flatter surface for taping .
,7. Which document is required by the Arizona Registrar of Contractors (ROC) to preserve a
contractor's right to file a mechanic's lien?
A. A signed contract
B. A preliminary 20-day notice
C. A Certificate of Occupancy
D. A warranty deed
Correct Answer: B. A preliminary 20-day notice
Rationale: In Arizona, a contractor must serve a preliminary notice (often referred to as a 20-day
notice) to the property owner within 20 days of first furnishing labor or materials to preserve their
right to later file a mechanic's lien. Without this notice, the right to a lien may be forfeited .
8. A crew is preparing to install drywall in a high-humidity bathroom. Which of the following is the
best practice for the project?
A. Install standard regular gypsum board.
B. Use moisture-resistant (greenboard) gypsum board.
C. Install standard drywall but apply a vapor barrier over it.
D. Use fire-resistant Type C board.
Correct Answer: B. Use moisture-resistant (greenboard) gypsum board.
Rationale: Moisture-resistant drywall, often referred to as greenboard, is specifically designed for use
in areas subject to high humidity, such as bathrooms and basements. It resists moisture absorption
better than regular drywall, helping to prevent mold and degradation of the board. While not for
direct water exposure, it is the standard choice for these applications .
9. What is the OSHA-mandated minimum height for a top guardrail on a scaffold?
A. 36 inches
B. 38 inches
C. 42 inches
D. 45 inches
Correct Answer: C. 42 inches
Rationale: OSHA regulation 29 CFR 1926.451(g)(4)(i) requires that the top edge of the guardrail on a
scaffold be between 38 and 45 inches. The most commonly specified and accepted minimum height is
42 inches .
10. A drywall contractor is preparing to attach 5/8-inch drywall to a ceiling. What is the standard
maximum screw spacing for this application?
A. 8 inches
B. 12 inches
C. 16 inches
D. 24 inches
, Correct Answer: B. 12 inches
Rationale: Because of gravity and the weight of the board, ceiling installations require closer fastener
spacing than walls. For 5/8-inch gypsum board on ceilings, the standard screw spacing is typically 12
inches on center . This prevents sagging.
11. What is the purpose of using a "control joint" in a large drywall installation?
A. To allow for expansion and contraction of the building, preventing random cracking
B. To provide a location for hanging heavy artwork
C. To create a design feature in the wall
D. To join two different thicknesses of drywall
Correct Answer: A. To allow for expansion and contraction of the building, preventing random
cracking
Rationale: In large expanses of drywall, internal stresses from building movement, temperature
changes, and moisture can cause unsightly random cracks. Control joints are engineered gaps built
into the partition that provide a planned point for movement, absorbing stress and preventing cracks
elsewhere .
12. A student is reviewing core concepts for the CR-10 exam. Which Arizona Revised Statutes
(A.R.S.) title governs the licensing and regulation of contractors?
A. Title 20
B. Title 28
C. Title 32
D. Title 42
Correct Answer: C. Title 32
Rationale: Title 32 of the Arizona Revised Statutes contains the laws governing professions and
occupations, including the licensing, regulation, and discipline of contractors by the Arizona Registrar
of Contractors .
13. When repairing a small hole in drywall, what method provides the most durable and
professional result?
A. Filling the hole with spackling compound only
B. Cutting out the damaged section and fitting a backer patch, then taping and mudding the seams
C. Covering the hole with a piece of trim
D. Gluing a mesh patch over the hole
Correct Answer: B. Cutting out the damaged section and fitting a backer patch, then taping and
mudding the seams
Rationale: For a long-lasting repair, the damaged area must be cut back to stable board. A piece of
drywall (a patch) is then fit into the hole and supported by a "backer" (e.g., a piece of wood behind
QUESTIONS AND VERIFIED ANSWERS | 2026–2027 LATEST
UPDATE | GUARANTEED PASS | DETAILED RATIONALES |
FULL STUDY GUIDE | EXAM PREP | PRACTICE TEST |
CERTIFICATION PREPARATION
1. A project specification calls for a wall assembly to achieve a 2-hour fire-resistance rating. Which
type of gypsum board is the most appropriate choice for the base layer?
A. 1/2-inch regular gypsum board
B. 5/8-inch Type X gypsum board
C. 1/2-inch moisture-resistant gypsum board
D. 1/4-inch gypsum board
Correct Answer: B. 5/8-inch Type X gypsum board
Rationale: Type X gypsum board is specially manufactured with non-combustible fibers, typically
fiberglass, to enhance its fire-resistive properties. It is the standard material used in fire-rated
assemblies to achieve ratings of 1 hour or more. Regular gypsum board lacks these additives and will
not provide the same level of protection .
2. When installing drywall over wood studs, which fastener provides the most secure and
consistent grip?
A. 1-1/4-inch coarse-thread drywall screws
B. 1-inch fine-thread drywall screws
C. 4d box nails
D. 1-1/2-inch drywall nails
Correct Answer: A. 1-1/4-inch coarse-thread drywall screws
Rationale: Coarse-thread drywall screws are specifically designed for attachment to wood framing.
The deep threads bite into the wood fibers, providing superior holding power compared to nails or
fine-thread screws . Fine-thread screws are intended for metal studs.
3. According to the International Building Code (IBC), what is the primary purpose of fire-blocking
within a wall assembly?
A. To provide additional insulation
B. To improve the sound transmission class (STC)
C. To prevent the vertical spread of fire and smoke within concealed spaces
D. To serve as a nailing base for trim
Correct Answer: C. To prevent the vertical spread of fire and smoke within concealed spaces
,Rationale: The IBC requires fire-blocking to cut off concealed draft openings, such as the cavities
between studs. This prevents fire from traveling vertically within the wall, slowing the spread of
flames and smoke through the building .
4. A superintendent on a commercial job site notices that a layer of frost has formed on the
gypsum board stored outside. What is the most appropriate course of action?
A. Proceed with installation as planned.
B. Move the boards inside and allow them to thaw completely before installation.
C. Wipe the frost off the boards and install them immediately.
D. Discard the boards as they are now structurally compromised.
Correct Answer: B. Move the boards inside and allow them to thaw completely before installation.
Rationale: Installing frost-laden or frozen gypsum board can lead to dimensional instability as the
water within the material thaws and evaporates, causing board movement, fastener pops, and joint
cracking. The boards must be allowed to warm up to the ambient temperature of the space where
they will be installed before the finishing process begins .
5. An acoustical ceiling grid system is being installed. What is the primary function of the "main
runner" or "main tee"?
A. To hold the tile edge in place
B. To be the primary load-carrying member supported by hanger wires
C. To connect the grid to the wall angle
D. To provide a decorative finish to the ceiling
Correct Answer: B. To be the primary load-carrying member supported by hanger wires
Rationale: The main runners are the heavy-gauge structural members that run the length of the
ceiling and are directly suspended from the structure above. All other components, such as cross tees,
are attached to the main runners, which bear the main load of the ceiling system .
6. Which of the following best describes the process of "back-butting" a drywall joint?
A. Applying a second layer of tape over a finished joint
B. Cutting a relief groove into the back of a board to prevent the edges from touching
C. Staggering the seams on the opposite side of a stud wall
D. Creating a V-groove on the face of the board for a decorative finish
Correct Answer: B. Cutting a relief groove into the back of a board to prevent the edges from
touching
Rationale: Back-butting is a technique used on drywall ends that are not tapered. A groove is cut or
scraped into the back of the board at the joint, allowing the thick, square edges to come together
without touching or "riding" over each other. This ensures a flatter surface for taping .
,7. Which document is required by the Arizona Registrar of Contractors (ROC) to preserve a
contractor's right to file a mechanic's lien?
A. A signed contract
B. A preliminary 20-day notice
C. A Certificate of Occupancy
D. A warranty deed
Correct Answer: B. A preliminary 20-day notice
Rationale: In Arizona, a contractor must serve a preliminary notice (often referred to as a 20-day
notice) to the property owner within 20 days of first furnishing labor or materials to preserve their
right to later file a mechanic's lien. Without this notice, the right to a lien may be forfeited .
8. A crew is preparing to install drywall in a high-humidity bathroom. Which of the following is the
best practice for the project?
A. Install standard regular gypsum board.
B. Use moisture-resistant (greenboard) gypsum board.
C. Install standard drywall but apply a vapor barrier over it.
D. Use fire-resistant Type C board.
Correct Answer: B. Use moisture-resistant (greenboard) gypsum board.
Rationale: Moisture-resistant drywall, often referred to as greenboard, is specifically designed for use
in areas subject to high humidity, such as bathrooms and basements. It resists moisture absorption
better than regular drywall, helping to prevent mold and degradation of the board. While not for
direct water exposure, it is the standard choice for these applications .
9. What is the OSHA-mandated minimum height for a top guardrail on a scaffold?
A. 36 inches
B. 38 inches
C. 42 inches
D. 45 inches
Correct Answer: C. 42 inches
Rationale: OSHA regulation 29 CFR 1926.451(g)(4)(i) requires that the top edge of the guardrail on a
scaffold be between 38 and 45 inches. The most commonly specified and accepted minimum height is
42 inches .
10. A drywall contractor is preparing to attach 5/8-inch drywall to a ceiling. What is the standard
maximum screw spacing for this application?
A. 8 inches
B. 12 inches
C. 16 inches
D. 24 inches
, Correct Answer: B. 12 inches
Rationale: Because of gravity and the weight of the board, ceiling installations require closer fastener
spacing than walls. For 5/8-inch gypsum board on ceilings, the standard screw spacing is typically 12
inches on center . This prevents sagging.
11. What is the purpose of using a "control joint" in a large drywall installation?
A. To allow for expansion and contraction of the building, preventing random cracking
B. To provide a location for hanging heavy artwork
C. To create a design feature in the wall
D. To join two different thicknesses of drywall
Correct Answer: A. To allow for expansion and contraction of the building, preventing random
cracking
Rationale: In large expanses of drywall, internal stresses from building movement, temperature
changes, and moisture can cause unsightly random cracks. Control joints are engineered gaps built
into the partition that provide a planned point for movement, absorbing stress and preventing cracks
elsewhere .
12. A student is reviewing core concepts for the CR-10 exam. Which Arizona Revised Statutes
(A.R.S.) title governs the licensing and regulation of contractors?
A. Title 20
B. Title 28
C. Title 32
D. Title 42
Correct Answer: C. Title 32
Rationale: Title 32 of the Arizona Revised Statutes contains the laws governing professions and
occupations, including the licensing, regulation, and discipline of contractors by the Arizona Registrar
of Contractors .
13. When repairing a small hole in drywall, what method provides the most durable and
professional result?
A. Filling the hole with spackling compound only
B. Cutting out the damaged section and fitting a backer patch, then taping and mudding the seams
C. Covering the hole with a piece of trim
D. Gluing a mesh patch over the hole
Correct Answer: B. Cutting out the damaged section and fitting a backer patch, then taping and
mudding the seams
Rationale: For a long-lasting repair, the damaged area must be cut back to stable board. A piece of
drywall (a patch) is then fit into the hole and supported by a "backer" (e.g., a piece of wood behind
