InterNACHI Structural Systems Evaluation 5 — Questions and Answers
Question 1: During a home inspection, the inspector notices that the double top plate on a load-bearing wall has a large splice in both plates directly above a door opening. What is the structural concern?
- The splice creates a visible seam that affects the drywall finish
- Splices directly over openings weaken the top plate where load transfer is most critical (Correct answer)
- The splice indicates the wrong nail pattern was used during framing
- Top plate splices are only acceptable in non-load-bearing walls
Correct answer: Splices directly over openings weaken the top plate where load transfer is most critical
Top plate splices must be offset from each other and from openings; splices directly over headers interrupt the load path at a critical transfer point.
Question 2: An inspector finds that a basement wall has been waterproofed on the interior using a crystalline waterproofing product. From a structural standpoint, what does this NOT address?
- Water vapor transmission through the concrete
- Lateral soil pressure that is causing the wall to bow inward (Correct answer)
- Minor surface seepage through hairline cracks
- Efflorescence on the interior wall surface
Correct answer: Lateral soil pressure that is causing the wall to bow inward
Interior waterproofing products address moisture intrusion but do nothing to relieve or resist the lateral soil pressure that causes structural wall movement.
Question 3: When inspecting a home built on expansive soils (clay), an inspector should be especially alert to which structural pattern?
- Uniform settlement of the entire foundation with level floors throughout
- Differential heaving or settlement causing doors to stick and diagonal cracks at opening corners (Correct answer)
- Horizontal cracking in foundation walls due to frost action
- Vertical cracks in exterior brick veneer along mortar joints
Correct answer: Differential heaving or settlement causing doors to stick and diagonal cracks at opening corners
Expansive soils swell when wet and shrink when dry, causing differential movement that leads to sticking doors, diagonal cracks at opening corners, and uneven floors.
Question 4: An inspector observes that the anchor bolts connecting the sill plate to the foundation are spaced 8 feet apart throughout a house in a high-wind zone. What is the concern?
- The anchor bolts may rust over time at that spacing
- Inadequate anchor bolt frequency reduces resistance to uplift and lateral forces from wind loads (Correct answer)
- The sill plate will not compress evenly during settling at 8-foot spacing
- Anchor bolt spacing only matters for seismic zones, not wind zones
Correct answer: Inadequate anchor bolt frequency reduces resistance to uplift and lateral forces from wind loads
In high-wind areas, anchor bolts must be spaced closely enough to resist uplift and shear forces; 8-foot spacing is typically inadequate and reduces the connection's structural capacity.
Question 5: What does the term 'cripple stud' refer to in wood-frame construction?
- A damaged stud that must be sistered for repair
- A short stud above or below a window or door opening that transfers loads to the header or rough sill (Correct answer)
- A diagonal brace stud used for racking resistance
- A doubled stud used at the corners of a wall frame
Correct answer: A short stud above or below a window or door opening that transfers loads to the header or rough sill
Cripple studs are short vertical framing members above door/window headers and below window rough sills that complete the wall framing around openings.
Question 6: An inspector observes that a wood deck is attached to the house with only nails through the ledger board into the band joist. Why is this a significant structural deficiency?
- Nails are not permitted by building codes for any exterior applications
- Nails can withdraw under repeated joist uplift forces, and the connection lacks resistance to ledger separation under deck loads (Correct answer)
- The nails will rust faster than approved fasteners, weakening the connection
- Only screws provide adequate shear transfer in ledger-to-band-joist connections
Correct answer: Nails can withdraw under repeated joist uplift forces, and the connection lacks resistance to ledger separation under deck loads
Ledger boards must be attached with through-bolts or approved structural screws because nails lack adequate withdrawal resistance and can pull out under sustained or dynamic deck loads.
Question 7: When evaluating a post-and-beam structure, an inspector notices that the beam-to-post connection relies solely on gravity (the beam simply rests on top of the post with no mechanical connection). What is the structural limitation?
- The connection cannot transfer compressive loads between beam and post
- The connection provides no resistance to uplift forces from wind or seismic events (Correct answer)
- Gravity connections are prohibited in post-and-beam construction by all building codes
- The beam may not be able to bear dead loads without a mechanical connection
Correct answer: The connection provides no resistance to uplift forces from wind or seismic events
A gravity-only connection transfers compressive loads adequately but provides no uplift resistance, making the structure vulnerable to overturning or uplift forces from wind or seismic activity.
InterNACHI Structural Systems Evaluation 5
During a home inspection, the inspector notices that the double top plate on a load-bearing wall has a large splice in both plates directly above a door opening.
What is the structural concern?