Structural Systems Evaluation Flashcards

During an inspection, the inspector finds that a steel I-beam in the basement has significant rust scaling and section loss. The MOST important evaluation is:

Answer: Whether the section loss has reduced the beam's load-carrying capacity

Rust scaling that causes section loss directly reduces the structural capacity of the steel beam and requires engineer evaluation to determine if replacement or reinforcement is needed.

What is the purpose of a ledger board when attached to a house for a deck?

Answer: To transfer deck loads to the house's structural framing

A ledger board is structural — it transfers vertical loads from the deck joists to the house's band joist or rim joist and must be properly bolted, not just nailed.

An inspector observes that a wood sill plate is soft and crumbles when probed with a screwdriver. What is the most likely cause and structural implication?

Answer: Wood decay from moisture has compromised the structural connection between foundation and framing

A soft, crumbling sill plate indicates wood decay, which destroys the critical structural link that transfers all wall and roof loads to the foundation.

Which method of foundation crack repair is considered MOST effective for stopping active water infiltration through a poured concrete wall?

Answer: Hydraulic cement injection or polyurethane foam injection into the crack

Polyurethane or epoxy injection into cracks seals them from within, addressing the actual infiltration pathway rather than just managing water after it enters.

When evaluating a crawl space, an inspector finds that the wood girder is supported by a masonry pier that is leaning noticeably. What is the primary concern?

Answer: The eccentric loading on the leaning pier could cause sudden buckling or collapse

A leaning masonry pier subjects itself to eccentric compressive loads that can cause sudden buckling failure, making it a significant structural safety concern.

An InterNACHI home inspector notices that the roof sheathing panels have visible gaps between them with no H-clips installed. What is the structural significance?

Answer: Without edge support, unsupported sheathing edges can deflect under load causing waves in the roof surface

H-clips provide edge support between rafters preventing unsupported sheathing edges from deflecting under load, which can cause visible waviness and eventual panel failure.

A home inspector observes that a cantilevered floor joist extending to support a bay window has developed a pronounced downward sag at its tip. This most likely indicates:

Answer: The cantilever length exceeds safe limits or the back-span anchorage is insufficient

Excessive cantilever length without adequate back-span anchorage allows the cantilevered joists to tip downward, often indicating a design or construction deficiency.