ICC 93 — Tall Mass Timber Buildings Special Inspector Exam |
Complete Questions with Verified Correct Answers & Detailed
Explanations –2026/2027 Update | Graded A+
Question 1
During inspection of a Type IV-A mass-timber building, the inspector
discovers that a structural mass-timber member does not comply with the
specified minimum dimensions for the construction type. The member is
otherwise structurally adequate. What is the MOST appropriate inspection
conclusion?
A. Accept it because structural capacity is the only consideration
B. Accept it if the member is concealed before final inspection
C. Document the nonconformance because the construction type includes
specific mass-timber requirements beyond structural capacity
D. Require replacement of every mass-timber member in the building
Correct Answer: C. Document the nonconformance because the
construction type includes specific mass-timber requirements beyond
structural capacity
Explanation:
Tall mass-timber construction depends on both structural and fire-
performance provisions. A member can be structurally adequate yet fail to
satisfy the requirements associated with the designated construction type.
The inspector should document the discrepancy and follow the approved
procedure for disposition of nonconforming work.
Question 2
Which group BEST represents common mass-timber structural products that
may be encountered in tall mass-timber construction?
A. CLT, glulam, SCL, NLT, and large-section sawn timber
B. PVC, gypsum board, aluminum foil, and glass fiber
1
,C. Brick veneer, asphalt shingles, and ceramic tile
D. Copper pipe, steel studs, and cement board only
Correct Answer: A. CLT, glulam, SCL, NLT, and large-section sawn timber
Explanation:
Mass timber encompasses several engineered and large-section wood
products. Cross-laminated timber (CLT), glued-laminated timber (glulam),
structural composite lumber (SCL), mechanically laminated decking such as
NLT, and large-section sawn timber are examples identified in ICC's mass-
timber material. (ICC)
Question 3
An inspector is examining a CLT floor panel installation. The approved
drawings require a specific panel orientation and connection arrangement.
The contractor installs the panels with the opposite orientation but claims the
panel has identical dimensions. What should the inspector do?
A. Accept the installation because dimensions are identical
B. Verify the approved design requirements and document the deviation
C. Approve it if the panels appear visually sound
D. Ignore the orientation because CLT is isotropic
Correct Answer: B. Verify the approved design requirements and
document the deviation
Explanation:
CLT panels are manufactured with directional laminations, and panel
orientation can affect structural performance and connection behavior. The
inspector should compare the installation with the approved construction
documents rather than making an independent engineering judgment.
Question 4
2
,A glulam beam arrives at the site with visible damage to a portion of its cross
section. The contractor proposes simply installing it because the damaged
area will be concealed by finishes. What should the inspector do?
A. Accept it because concealed damage has no structural significance
B. Document the damage and refer it for evaluation according to the approved
procedures
C. Sand the damaged area and approve it
D. Apply paint and continue inspection
Correct Answer: B. Document the damage and refer it for evaluation
according to the approved procedures
Explanation:
Structural timber damage cannot be dismissed simply because it will later be
concealed. Damage can affect structural capacity, fire performance, durability,
or connection behavior. The inspector should document the condition and
obtain the required evaluation or corrective action.
Question 5
During inspection of a mass-timber column, the inspector observes an
unauthorized field-cut penetration through the member. Why is this
particularly important?
A. Field modifications can affect structural capacity and potentially required
fire protection
B. All wood members are permitted unlimited field modifications
C. A penetration only affects appearance
D. The penetration automatically increases fire resistance
Correct Answer: A. Field modifications can affect structural capacity and
potentially required fire protection
Explanation:
Unapproved penetrations can reduce the effective cross section, interfere with
connections, create stress concentrations, and affect required protection.
Structural mass timber should not be modified in the field unless the
modification is specifically permitted or approved.
3
, Question 6
A Type IV-A building is being inspected. Which statement BEST describes the
significance of the Type IV-A designation?
A. It is one of the mass-timber construction types established to permit
greater use of mass timber in taller buildings under the applicable IBC
provisions
B. It is exclusively a steel construction type
C. It eliminates fire-resistance requirements
D. It is a nonstructural interior finish classification
Correct Answer: A. It is one of the mass-timber construction types
established to permit greater use of mass timber in taller buildings
under the applicable IBC provisions
Explanation:
The 2021 IBC introduced Types IV-A, IV-B, and IV-C as new mass-timber
construction types allowing greater building heights, stories, and areas than
earlier heavy-timber provisions under applicable conditions. (ICC Store)
Question 7
Which construction types were specifically introduced in the 2021 IBC to
expand the use of mass timber in taller buildings?
A. Types II-A, II-B, and III-A
B. Types IV-A, IV-B, and IV-C
C. Types V-A, V-B, and VI-A
D. Types I-A, I-B, and I-C
Correct Answer: B. Types IV-A, IV-B, and IV-C
Explanation:
The 2021 IBC introduced three new construction types—IV-A, IV-B, and IV-C
—for expanded tall mass-timber construction. These provisions represented a
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Complete Questions with Verified Correct Answers & Detailed
Explanations –2026/2027 Update | Graded A+
Question 1
During inspection of a Type IV-A mass-timber building, the inspector
discovers that a structural mass-timber member does not comply with the
specified minimum dimensions for the construction type. The member is
otherwise structurally adequate. What is the MOST appropriate inspection
conclusion?
A. Accept it because structural capacity is the only consideration
B. Accept it if the member is concealed before final inspection
C. Document the nonconformance because the construction type includes
specific mass-timber requirements beyond structural capacity
D. Require replacement of every mass-timber member in the building
Correct Answer: C. Document the nonconformance because the
construction type includes specific mass-timber requirements beyond
structural capacity
Explanation:
Tall mass-timber construction depends on both structural and fire-
performance provisions. A member can be structurally adequate yet fail to
satisfy the requirements associated with the designated construction type.
The inspector should document the discrepancy and follow the approved
procedure for disposition of nonconforming work.
Question 2
Which group BEST represents common mass-timber structural products that
may be encountered in tall mass-timber construction?
A. CLT, glulam, SCL, NLT, and large-section sawn timber
B. PVC, gypsum board, aluminum foil, and glass fiber
1
,C. Brick veneer, asphalt shingles, and ceramic tile
D. Copper pipe, steel studs, and cement board only
Correct Answer: A. CLT, glulam, SCL, NLT, and large-section sawn timber
Explanation:
Mass timber encompasses several engineered and large-section wood
products. Cross-laminated timber (CLT), glued-laminated timber (glulam),
structural composite lumber (SCL), mechanically laminated decking such as
NLT, and large-section sawn timber are examples identified in ICC's mass-
timber material. (ICC)
Question 3
An inspector is examining a CLT floor panel installation. The approved
drawings require a specific panel orientation and connection arrangement.
The contractor installs the panels with the opposite orientation but claims the
panel has identical dimensions. What should the inspector do?
A. Accept the installation because dimensions are identical
B. Verify the approved design requirements and document the deviation
C. Approve it if the panels appear visually sound
D. Ignore the orientation because CLT is isotropic
Correct Answer: B. Verify the approved design requirements and
document the deviation
Explanation:
CLT panels are manufactured with directional laminations, and panel
orientation can affect structural performance and connection behavior. The
inspector should compare the installation with the approved construction
documents rather than making an independent engineering judgment.
Question 4
2
,A glulam beam arrives at the site with visible damage to a portion of its cross
section. The contractor proposes simply installing it because the damaged
area will be concealed by finishes. What should the inspector do?
A. Accept it because concealed damage has no structural significance
B. Document the damage and refer it for evaluation according to the approved
procedures
C. Sand the damaged area and approve it
D. Apply paint and continue inspection
Correct Answer: B. Document the damage and refer it for evaluation
according to the approved procedures
Explanation:
Structural timber damage cannot be dismissed simply because it will later be
concealed. Damage can affect structural capacity, fire performance, durability,
or connection behavior. The inspector should document the condition and
obtain the required evaluation or corrective action.
Question 5
During inspection of a mass-timber column, the inspector observes an
unauthorized field-cut penetration through the member. Why is this
particularly important?
A. Field modifications can affect structural capacity and potentially required
fire protection
B. All wood members are permitted unlimited field modifications
C. A penetration only affects appearance
D. The penetration automatically increases fire resistance
Correct Answer: A. Field modifications can affect structural capacity and
potentially required fire protection
Explanation:
Unapproved penetrations can reduce the effective cross section, interfere with
connections, create stress concentrations, and affect required protection.
Structural mass timber should not be modified in the field unless the
modification is specifically permitted or approved.
3
, Question 6
A Type IV-A building is being inspected. Which statement BEST describes the
significance of the Type IV-A designation?
A. It is one of the mass-timber construction types established to permit
greater use of mass timber in taller buildings under the applicable IBC
provisions
B. It is exclusively a steel construction type
C. It eliminates fire-resistance requirements
D. It is a nonstructural interior finish classification
Correct Answer: A. It is one of the mass-timber construction types
established to permit greater use of mass timber in taller buildings
under the applicable IBC provisions
Explanation:
The 2021 IBC introduced Types IV-A, IV-B, and IV-C as new mass-timber
construction types allowing greater building heights, stories, and areas than
earlier heavy-timber provisions under applicable conditions. (ICC Store)
Question 7
Which construction types were specifically introduced in the 2021 IBC to
expand the use of mass timber in taller buildings?
A. Types II-A, II-B, and III-A
B. Types IV-A, IV-B, and IV-C
C. Types V-A, V-B, and VI-A
D. Types I-A, I-B, and I-C
Correct Answer: B. Types IV-A, IV-B, and IV-C
Explanation:
The 2021 IBC introduced three new construction types—IV-A, IV-B, and IV-C
—for expanded tall mass-timber construction. These provisions represented a
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