InterNACHI Roof Inspector common mistakes
InterNACHI Roof Inspector · Understand the traps and how to avoid them.
Describing the roof covering as the whole roof assembly and omitting underlayment, flashing, decking, and ventilation when a question asks to identify roof components.
Candidates study shingle types and profiles visually and treat the visible surface as the system, so they forget the layered assembly and the role of each layer in shedding water.
What to do instead
Before answering any components question, mentally list the full stack from deck upward (decking, underlayment, flashing, covering, ridge and eave ventilation) and state the function of each layer; practice drawing the stack from memory for asphalt, tile, metal, and low-slope membrane roofs.
Treating all steep-slope and low-slope products as interchangeable, for example accepting a standard three-tab shingle or tile on a 2:12 slope or calling a modified bitumen membrane a steep-slope covering.
Candidates memorize product names without attaching minimum slope thresholds, so they cannot match a material to a roof pitch when the question gives a slope.
What to do instead
Build a slope-to-material table (asphalt shingles generally 2:12 and up with underlayment requirements below 4:12, tile and metal per manufacturer, membranes for low slope) and drill matching each product to its minimum slope and required underlayment before answering.
Climbing or walking a roof without first assessing pitch, surface condition, weather, and anchor availability, or failing to state a safe alternative when conditions are marginal.
Candidates want to demonstrate competence by going onto the roof and skip the pre-access decision, forgetting that the standard of practice permits alternate methods and that the inspector decides access.
What to do instead
Practice a scripted pre-access check (pitch, covering type and condition, moisture, wind, temperature, edge fall hazard, ladder footing) and rehearse stating when and how you would decline roof walking and use binoculars, a ladder at the eave, or a drone instead.
Setting up a ladder at the wrong angle, above the eave line, or without securing the top and footing, and then describing that setup as acceptable in an exam scenario.
Ladder placement is learned by habit rather than by rule, so candidates cannot recall the one-quarter rule, the three-foot extension above the eave, or the requirement to tie off or foot the ladder.
What to do instead
Memorize the ladder rules as checkable numbers (base one foot out per four feet of height, extend about three feet above the eave, maintain three points of contact, secure the top, keep the base on firm level ground) and answer ladder questions by checking each number against the scenario.
Reporting a cosmetic condition such as granule loss, staining, or mild surface cracking as a definite functional failure, or the reverse, dismissing a condition that indicates active water entry.
Candidates confuse visible wear with performance failure and lack a framework for separating appearance issues from conditions that compromise the roof's water-shedding function.
What to do instead
For each defect, ask whether it affects water shedding, structural integrity, or safety now or soon; classify into cosmetic, monitor, maintenance, or defect and justify the classification with the mechanism (for example staining under a flashing termination suggests active entry, scattered granule loss in gutters suggests normal aging).
Missing the common leak locations and reporting only the field of the roof, without inspecting and commenting on valleys, penetrations, step and counterflashing, chimney and skylight curbs, and eave and rake edges.
The field of the roof dominates the visual field and is easy to scan, while flashings are small, often hidden, and require deliberate attention at transitions.
What to do instead
Adopt a fixed inspection route that visits every transition and penetration in the same order each time, and practice writing a finding for each location even when it is serviceable, so no transition is skipped under time pressure.
Inspecting the attic and roof underside only from the hatch or not at all, missing evidence of decking deterioration, active leaks, condensation, or inadequate ventilation that the exterior does not reveal.
Attic access is uncomfortable and sometimes obstructed, so candidates limit themselves to what is visible from the opening and do not connect interior evidence to exterior roof conditions.
What to do instead
Treat the attic as a required part of the roof inspection: walk or view the underside of the decking where safely accessible, look for staining, delamination, frost, mold, and blocked soffit or ridge vents, and practice reporting the limits of what you could not see.
Writing findings that state a defect without location, description, implication, and recommended action, or using vague language such as 'roof appears worn' with no basis.
Candidates draft reports as notes to themselves rather than as a document a client and contractor can act on, and they lack a consistent finding template.
What to do instead
Use a four-part finding format (location, observed condition, implication, recommendation) and rewrite sample findings until each one is specific enough that a contractor could locate and price the repair from the report alone.
Exceeding the standards of practice by offering a remaining service life estimate, a code-compliance ruling, or a warranty opinion, or by implying the inspection is a guarantee that the roof will not leak.
Clients ask for these opinions and candidates want to be helpful, so they drift past the scope without recognizing the liability and the standards boundary.
What to do instead
Memorize the scope and limitations language of the standards of practice and practice declining those requests with an accurate alternative (describe observed condition and recommend evaluation by a qualified roofing contractor), then keep the same wording in every report.
Failing to record and disclose the limitations of the roof inspection, such as areas not accessed, snow cover, or restricted visibility, so the report reads as a complete inspection of the entire roof.
Candidates focus on what they found and omit what they could not examine, not realizing that an unstated limitation is the most common source of later disputes.
What to do instead
End every roof section with an explicit access and limitation statement listing methods used, areas viewed and not viewed, and conditions that masked the surface, and review reports to confirm the limitation matches the method actually used.