NHIE Structural Systems 3 — Questions and Answers
Question 1: Which condition would a home inspector identify as most structurally significant when examining wood floor joists?
- Joists spaced 16 inches on center
- Joists with splits running along the grain at mid-span (Correct answer)
- Joists with a single coat of paint
- Joists installed with crown up
Correct answer: Joists with splits running along the grain at mid-span
Longitudinal splits (checks) along the grain at mid-span reduce the effective depth of the joist and its bending capacity, representing a structural concern.
Question 2: What is the function of anchor bolts in residential construction?
- To connect floor joists to girders
- To connect the sill plate to the foundation wall (Correct answer)
- To secure roof trusses to bearing walls
- To tie gable end walls to rafters
Correct answer: To connect the sill plate to the foundation wall
Anchor bolts embed in the concrete foundation and secure the sill plate, preventing the structure from sliding or lifting off the foundation during high winds or seismic events.
Question 3: Stair stringers that are cut too deeply can fail in which way?
- Delamination of wood layers
- Breakage at the notch due to inadequate remaining material (Correct answer)
- Excessive deflection of treads
- Splitting of the riser boards
Correct answer: Breakage at the notch due to inadequate remaining material
Over-cutting notches in a stair stringer leaves insufficient material in the remaining cross-section, causing the stringer to break at the notch under load.
Question 4: A home inspector notices that several roof trusses have been field-cut to allow for HVAC installation. This is a concern because:
- It voids the HVAC warranty
- Truss members must not be cut or modified without an engineer's approval (Correct answer)
- It increases attic ventilation
- It only matters for bottom chord cuts
Correct answer: Truss members must not be cut or modified without an engineer's approval
Roof trusses are engineered systems where every member is load-bearing; any field modification, including cutting, requires engineer approval to ensure structural integrity.
Question 5: What does 'settlement' refer to in the context of a residential foundation?
- The legal transfer of property ownership
- Downward movement of the foundation due to soil compression under load (Correct answer)
- Curing shrinkage of concrete
- Seismic displacement of the structure
Correct answer: Downward movement of the foundation due to soil compression under load
Settlement is the downward movement of a foundation as the soil beneath compresses under the structural load, which can be uniform (benign) or differential (damaging).
Question 6: Which of the following is an indicator of roof rafter spread at the exterior walls?
- Cracked chimney mortar
- Walls bowing outward and ridge sagging (Correct answer)
- Missing soffit vents
- Lifted roof shingles at the ridge
Correct answer: Walls bowing outward and ridge sagging
Rafter spread occurs when ceiling joists or collar ties fail to resist outward thrust from rafters, causing exterior walls to bow out and the ridge to sag downward.
Question 7: What is the primary structural role of cripple studs in wall framing?
- They provide lateral shear resistance
- They transfer loads above and below window and door openings to headers and sills (Correct answer)
- They are decorative non-structural members
- They replace king studs at corners
Correct answer: They transfer loads above and below window and door openings to headers and sills
Cripple studs are short studs above and below openings that transfer loads from the top plate to the header, and from the rough sill to the bottom plate.
NHIE Structural Systems 3
Which condition would a home inspector identify as most structurally significant when examining wood floor joists?