INTERNACHI Cheat Sheet 2026

The 30 highest-yield INTERNACHI facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. When inspecting a crawl space with a ground vapor barrier, what deficiency should an inspector note if the barrier is not sealed at the perimeter walls? → Moisture will migrate from exposed soil edges into the crawl space air
2. What type of insulation is commonly identified by its pink, yellow, or white fibrous appearance and is most often found in attic floors? → Fiberglass batt or blown insulation
3. Which of the following is a common defect found with older two-prong (ungrounded) receptacles? → They have no equipment grounding conductor, offering no protection against faults
4. When inspecting wood siding, which condition most strongly suggests active moisture intrusion? → Cupping or buckling of boards
5. A homeowner reports that one room is always too hot in summer despite the AC running. Which inspection finding is most likely the cause? → Blocked or disconnected supply duct to that room
6. An inspector observes a service entrance cable with damaged outer insulation at the weatherhead. What is the primary concern? → Water intrusion causing corrosion inside the meter base
7. Under InterNACHI standards, what does 'readily accessible' mean in the context of a home inspection? → Exposed and able to be observed without moving obstacles
8. What is the purpose of a weep screed at the base of stucco cladding? → To allow moisture trapped behind stucco to drain out
9. An inspector observes that a wood girder in a crawl space shows significant end decay where it enters a masonry pocket. What is the most likely cause? → Trapped moisture from condensation or water intrusion in the masonry pocket
10. An inspector sees that a downspout terminates at the foundation wall with no extension. What is the recommended correction? → Add a splash block or extension to direct water at least 6 feet from the foundation
11. When inspecting supply ducts in an unconditioned attic, an inspector should be most concerned about: → Missing or inadequate insulation on ducts
12. How does moisture affect structural components? → It causes deterioration and damage
13. What is a common plumbing issue in homes? → Pipe leaks
14. What does a home inspector look for when evaluating whether blown-in cellulose insulation in an attic has settled significantly? → Depth ruler markings on attic trusses or joists indicating original fill depth
15. Which type of retaining wall deficiency is considered a safety hazard during an exterior inspection? → Leaning or bulging wall with no weep holes
16. Which component of a wood-burning stove installation does an inspector evaluate for safe clearance to combustibles? → The stovepipe, stove body, and floor protector clearances per manufacturer and code
17. What is the function of a condensate neutralizer on a high-efficiency condensing furnace? → It raises the pH of acidic condensate before it enters the drain
18. When inspecting a metal roof, an inspector notices white, powdery deposits near fasteners. What does this indicate? → Galvanic corrosion from dissimilar metals in contact
19. A home inspector finds a 15-amp breaker protecting a circuit with 12 AWG wire. This is: → Acceptable — the wire exceeds the breaker's ampacity rating
20. An inspector discovers a sealed attic hatch that has never been opened. Under InterNACHI standards, what is the correct action? → Note the limitation and inspect as much of the attic as is accessible
21. Which of the following is a sign of a failing supply stop valve under a sink? → Mineral deposits or corrosion around the valve packing nut
22. According to NEC, GFCI protection is required in which of the following locations? → Bathroom receptacles
23. What is the primary structural purpose of cross-bridging or blocking between floor joists? → To prevent lateral rotation and distribute loads between joists
24. What is the role of structural engineers in home inspections? → To inspect and design structural components
25. When inspecting exterior stairs, what baluster spacing deficiency is a safety hazard? → Baluster spacing greater than 4 inches, allowing a child's head to pass through
26. What is the primary purpose of a vapor retarder installed on the warm-in-winter side of an insulated wall? → To stop moisture-laden air from diffusing into the wall and condensing
27. According to InterNACHI standards, when inspecting a home with multiple HVAC systems, what is required? → All permanently installed heating and cooling systems must be inspected
28. An inspector observes that a deck ledger board is attached directly to the house band joist without flashing. What hazard does this present? → Water can infiltrate behind the ledger, causing rot and structural failure
29. What is the purpose of a ledger board when attached to a house for a deck? → To transfer deck loads to the house's structural framing
30. An inspector finds galvanized steel supply pipes in an older home. The most likely concern is: → Internal corrosion reducing water flow and pressure