National Home Inspector Examination® (NHIE) common mistakes
NHIE · Understand the traps and how to avoid them.
Calling out a foundation crack as a structural defect before determining whether it is hairline shrinkage, a vertical crack at a control joint, or a diagonal crack at a corner, and writing it up without measuring width, offset, or displacement.
Candidates memorize the phrase 'foundation crack equals defect' and skip the observation step. The NHIE structural items test whether you can distinguish cosmetic shrinkage cracking from differential settlement or a horizontal shear crack, and inspection candidates often report the crack without documenting the size and pattern that drive the conclusion.
What to do instead
Before writing any narrative, record crack width in fractions of an inch, orientation (vertical, diagonal, horizontal, stair-step), location relative to corners and openings, and any offset or lateral displacement. Then state the implication: hairline vertical shrinkage cracks are typically not structural, while horizontal cracks in a block foundation or stair-step cracks at a corner with displacement warrant a structural engineer referral. Practice this on photos until the observation-to-conclusion sequence is automatic.
Treating a missing or improperly terminated roof-to-wall connection, or a notched or over-cut floor joist, as a minor item rather than a structural alteration, and failing to flag the load path break.
Candidates focus on visible cosmetic conditions and do not trace load paths. Notches and holes in joists, cut trusses, and removed bearing walls are common in remodeled homes, and the exam tests whether the inspector recognizes that a cut bottom chord or an over-notched joist changes the structural capacity of the member.
What to do instead
Learn the standard limits for notching and boring (for example, notches in the top or bottom of solid-sawn joists limited to one-quarter of depth at bearing points, holes kept away from the top and bottom edges, and no notching in the middle third of the span). When you see a cut truss or a removed wall, describe the modification, note that engineering approval is not documented, and recommend evaluation by a licensed structural engineer rather than guessing at adequacy.
Reporting deck ledger attachment and flashing as acceptable based on a visual glance from the ground, without checking for ledger fastening pattern, lag or through-bolt spacing, and proper flashing over the ledger.
Decks are the most common source of structural collapse and the ledger connection is usually hidden behind siding or below the deck surface. Candidates who do not walk the deck, look under it, or check fastener spacing miss the condition entirely and write 'deck appears serviceable,' which is exactly the error the exam probes.
What to do instead
Adopt a fixed deck checklist: access under the deck, verify ledger attachment method and spacing, look for corrosion or withdrawal of fasteners, confirm flashing and kick-out at the ledger, check post-to-footing connections, and verify diagonal bracing or joist-to-beam connection hardware. If the underside is not accessible, say so explicitly and recommend further evaluation rather than implying the connection was verified.
Describing an HVAC or plumbing defect only as 'unit is old' or 'water heater is near end of life' instead of identifying the specific defect, its safety implication, and the corrective action.
Candidates default to age-based language because it feels safe, but the mechanical items on the exam test whether you can identify a missing TPR discharge pipe, an improperly terminated discharge, a backdrafting flue, a missing sediment trap, or an undersized gas connector. Age alone is not a defect and the exam rewards condition-specific findings.
What to do instead
For every mechanical finding, write three parts: the observed condition, the consequence if uncorrected, and the recommended action. For example, instead of 'water heater is aging,' write that the TPR valve has no discharge pipe extending to within six inches of the floor, which creates a scald and pressure hazard, and recommend installation by a licensed plumber. Drill this format until it is reflexive.
Failing to test or describe the operation of safety devices such as the furnace flame sensor, the draft hood, the condensate line, and the water heater TPR valve, and omitting combustion air and venting observations.
Candidates are uncomfortable operating equipment or lighting pilots and skip functional testing, then write a generic 'heating system operated normally.' The exam includes items on backdrafting, vent connector slope, and combustion air supply because these are the conditions inspectors most often miss.
What to do instead
Follow a consistent sequence for each fuel-burning appliance: confirm the vent connector rises toward the chimney, check for a draft hood and adequate clearance to combustibles, verify combustion air openings, observe flame color and characteristics, and test the TPR valve and discharge pipe on water heaters. Note in the report exactly what was and was not operated, so the scope is clear.
Ignoring the electrical service panel's labeling of double-tapped breakers, undersized conductors, and missing bonding of gas and water piping, and reporting only 'panel appears functional.'
Mechanical and electrical findings overlap in the exam's mechanical domain when appliances are improperly connected, and candidates often defer to 'licensed electrician should evaluate' without stating the specific defect. That vague referral does not demonstrate the competency the exam measures.
What to do instead
Photograph and describe the specific condition: two conductors under one breaker terminal not listed for that use, a breaker oversized for the conductor, a missing bonding jumper across the water meter, or a gas appliance connector passing through a wall. State the defect, the risk, and the referral. Keep a written list of the top panel conditions you check every time.
Writing recommendations as 'further evaluation recommended' without naming the trade, the specific condition, and the reason, so the client cannot act on the report.
Candidates learn that inspectors should not prescribe repairs and overcorrect into vague language. The exam distinguishes between disclaiming design responsibility and providing a clear, actionable observation, and vague reports fail the second standard.
What to do instead
Use a three-part recommendation template: condition observed, implication, and who should evaluate or repair. For example, 'The chimney flue has deteriorated mortar joints visible in the attic; this can allow flue gases into the home; recommend evaluation and repair by a licensed chimney specialist before use.' This satisfies the no-prescription rule while remaining specific.
Misunderstanding the scope of the standards of practice and reporting on systems or components the inspector did not actually inspect, such as concealed framing, the interior of the flue, or the condition of a septic system's drain field.
Candidates want to appear thorough and describe conditions inferred from indirect evidence as if observed. The exam tests whether you can state the limits of a visual, non-invasive inspection and accurately describe what was excluded.
What to do instead
Memorize the standard exclusion categories for the relevant standards of practice and write them into the report template: concealed components, underground items, systems shut down or not operated, and items obscured by stored goods or finishes. When you infer a condition, label it as an inference and explain the basis. Never describe an uninspected system in definitive terms.
Mixing personal opinion and repair cost estimates into the report, or offering to perform the repairs identified, without addressing the conflict of interest and the limits on the inspector's role.
Candidates blend advisory language with contracting language because clients ask 'what will this cost?' The business domain tests the boundary between inspection and contracting, and also tests whether the inspector understands that recommending a contractor with whom there is a financial relationship creates a conflict.
What to do instead
Keep the report to condition and recommendation, with no cost estimates and no offers to repair. If your jurisdiction restricts repair work by inspectors on inspected properties within a defined period, know that rule and disclose any referral relationships in writing. When asked about cost, explain that pricing is outside the inspection scope and refer the client to qualified contractors.
Treating the pre-inspection agreement, the report delivery timeline, and record retention as paperwork to handle after the inspection, and skipping a written statement of scope and limitations before the inspection begins.
Candidates concentrate on technical content and underestimate the business-risk items on the exam. The agreement, the scope statement, and the delivery deadline define the inspector's exposure, and failing to document them is a common reason reports become disputed.
What to do instead
Build a pre-inspection package you deliver and have signed before the walkthrough: agreement with scope, exclusions, limitation of liability where permitted, fee, and delivery date. Calendar the delivery deadline and retain the report and communication records for the period your state or the relevant standard requires. Review the package once per quarter as rules change.