ICC 93 TALL MASS TIMBER BUILDINGS SPECIAL INSPECTOR
EXAM ADVANCED PRACTICE QUESTION BANK – 2026/2027
EDITION | 200 QUESTIONS
1. A special inspector is reviewing the construction documents for a
proposed Type IV-B mass timber building. The architect has specified
that the primary structural frame will be fully exposed glulam. What is
the inspector's most appropriate action?
A. Approve the plans because glulam is inherently fire-resistant.
B. Reject the plans because Type IV-B construction limits exposed
mass timber on the primary structural frame.
C. Approve the plans if the building is equipped with an automatic
sprinkler system.
D. Approve the plans if the glulam is treated with a fire-retardant
coating.
Rationale: Type IV-B construction permits limited exposure of mass
timber on walls and ceilings but does not permit full exposure of the
primary structural frame. The inspector should reject the plans because
they do not comply with the code provisions for Type IV-B construction.
2. During a special inspection of a Type IV-A building under
construction, the inspector observes that a CLT floor panel is being
installed with a 2-inch gap at the perimeter. The contractor states the
gap will be filled with spray foam insulation. What should the
inspector do?
,A. Accept the installation because spray foam is an approved firestop
material.
B. Accept the installation if the gap is less than 4 inches.
C. Reject the installation because the gap must be protected with an
approved fire-resistance-rated joint system.
D. Reject the installation because gaps are never permitted in CLT floor
panels.
Rationale: Gaps and joints between mass timber elements must be
protected with approved fire-resistance-rated joint systems to maintain
the required fire-resistance rating of the assembly. Spray foam alone is
not an approved fire-resistance-rated joint system.
3. Which of the following statements best describes the role of a
special inspector for a tall mass timber project?
A. The special inspector is responsible for designing the structural
connections.
B. The special inspector verifies that construction complies with the
approved plans and applicable code requirements.
C. The special inspector supervises the construction crew to ensure
proper installation.
D. The special inspector approves changes to the structural design.
Rationale: The special inspector's primary role is to verify compliance
with the approved plans, code requirements, and project specifications.
The special inspector does not design connections, supervise crews, or
approve design changes.
,4. A contractor is installing self-tapping screws in a CLT shear wall
connection. The inspector notices that the screws are being installed
at an angle different from that specified in the approved plans. What
should the inspector do?
A. Allow the installation to continue because the angle difference is
minor.
B. Stop the work and require the contractor to verify that the
installation angle meets the design requirements.
C. Approve the installation if the screws are longer than specified.
D. Approve the installation if the screws are the correct diameter.
Rationale: Screw installation angle is critical to the structural
performance of the connection. The inspector should stop the work and
require verification that the installation meets the design requirements.
5. Under the 2024 IBC, what is the maximum permitted height for a
Type IV-B building with a Group B occupancy?
A. 85 feet
B. 180 feet
C. 270 feet
D. 120 feet
Rationale: Type IV-B construction is permitted up to 180 feet in height.
The 2024 IBC maintains this height limit for Type IV-B construction.
6. Which of the following is the correct nominal design char rate for
mass timber per the NDS?
, A. 0.5 inches per hour
B. 1.0 inches per hour
C. 1.5 inches per hour
D. 2.0 inches per hour
Rationale: The NDS establishes a nominal design char rate of 1.5 inches
per hour. This rate is used to calculate the fire-resistance rating of mass
timber elements.
7. During construction of a Type IV-C building, the inspector observes
that concealed spaces are being created between the CLT floor panels
and the suspended ceiling. What is the most appropriate action?
A. Accept the concealed space because it is less than 100 square feet.
B. Accept the concealed space if it is sprinklered.
C. Verify that the concealed space is protected with noncombustible
construction.
D. Reject all concealed spaces in mass timber buildings.
Rationale: In Type IV-C construction, concealed spaces are allowed if
they are protected with noncombustible construction. The inspector
should verify that this requirement is met.
8. A special inspector is reviewing the mill certificates for a CLT
project. The moisture content of the panels is listed as 30%. What is
the inspector's most appropriate action?
A. Reject the panels because the moisture content exceeds 15%.
B. Accept the panels because the moisture content does not exceed
EXAM ADVANCED PRACTICE QUESTION BANK – 2026/2027
EDITION | 200 QUESTIONS
1. A special inspector is reviewing the construction documents for a
proposed Type IV-B mass timber building. The architect has specified
that the primary structural frame will be fully exposed glulam. What is
the inspector's most appropriate action?
A. Approve the plans because glulam is inherently fire-resistant.
B. Reject the plans because Type IV-B construction limits exposed
mass timber on the primary structural frame.
C. Approve the plans if the building is equipped with an automatic
sprinkler system.
D. Approve the plans if the glulam is treated with a fire-retardant
coating.
Rationale: Type IV-B construction permits limited exposure of mass
timber on walls and ceilings but does not permit full exposure of the
primary structural frame. The inspector should reject the plans because
they do not comply with the code provisions for Type IV-B construction.
2. During a special inspection of a Type IV-A building under
construction, the inspector observes that a CLT floor panel is being
installed with a 2-inch gap at the perimeter. The contractor states the
gap will be filled with spray foam insulation. What should the
inspector do?
,A. Accept the installation because spray foam is an approved firestop
material.
B. Accept the installation if the gap is less than 4 inches.
C. Reject the installation because the gap must be protected with an
approved fire-resistance-rated joint system.
D. Reject the installation because gaps are never permitted in CLT floor
panels.
Rationale: Gaps and joints between mass timber elements must be
protected with approved fire-resistance-rated joint systems to maintain
the required fire-resistance rating of the assembly. Spray foam alone is
not an approved fire-resistance-rated joint system.
3. Which of the following statements best describes the role of a
special inspector for a tall mass timber project?
A. The special inspector is responsible for designing the structural
connections.
B. The special inspector verifies that construction complies with the
approved plans and applicable code requirements.
C. The special inspector supervises the construction crew to ensure
proper installation.
D. The special inspector approves changes to the structural design.
Rationale: The special inspector's primary role is to verify compliance
with the approved plans, code requirements, and project specifications.
The special inspector does not design connections, supervise crews, or
approve design changes.
,4. A contractor is installing self-tapping screws in a CLT shear wall
connection. The inspector notices that the screws are being installed
at an angle different from that specified in the approved plans. What
should the inspector do?
A. Allow the installation to continue because the angle difference is
minor.
B. Stop the work and require the contractor to verify that the
installation angle meets the design requirements.
C. Approve the installation if the screws are longer than specified.
D. Approve the installation if the screws are the correct diameter.
Rationale: Screw installation angle is critical to the structural
performance of the connection. The inspector should stop the work and
require verification that the installation meets the design requirements.
5. Under the 2024 IBC, what is the maximum permitted height for a
Type IV-B building with a Group B occupancy?
A. 85 feet
B. 180 feet
C. 270 feet
D. 120 feet
Rationale: Type IV-B construction is permitted up to 180 feet in height.
The 2024 IBC maintains this height limit for Type IV-B construction.
6. Which of the following is the correct nominal design char rate for
mass timber per the NDS?
, A. 0.5 inches per hour
B. 1.0 inches per hour
C. 1.5 inches per hour
D. 2.0 inches per hour
Rationale: The NDS establishes a nominal design char rate of 1.5 inches
per hour. This rate is used to calculate the fire-resistance rating of mass
timber elements.
7. During construction of a Type IV-C building, the inspector observes
that concealed spaces are being created between the CLT floor panels
and the suspended ceiling. What is the most appropriate action?
A. Accept the concealed space because it is less than 100 square feet.
B. Accept the concealed space if it is sprinklered.
C. Verify that the concealed space is protected with noncombustible
construction.
D. Reject all concealed spaces in mass timber buildings.
Rationale: In Type IV-C construction, concealed spaces are allowed if
they are protected with noncombustible construction. The inspector
should verify that this requirement is met.
8. A special inspector is reviewing the mill certificates for a CLT
project. The moisture content of the panels is listed as 30%. What is
the inspector's most appropriate action?
A. Reject the panels because the moisture content exceeds 15%.
B. Accept the panels because the moisture content does not exceed
