InterNACHI Standards of Practice and Reporting
Scope of the Standards of Practice
InterNACHI's SOP requires the inspector to inspect attached and detached decks, balconies, stoops, steps, porches, and their railings and means of attachment, and to report observed defects. It does not require determining code compliance, calculating load capacity, or predicting remaining service life, and a deck underside that is not readily accessible may be reported as not inspected with the reason stated.
Structure every finding
Location → observation → implication → recommendation. "Rear deck, ledger-to-rim connection: three fasteners are missing and the remaining lags are corroded; the ledger is relying on a few fasteners to carry the deck; recommend evaluation and repair by a licensed contractor before further use." That sentence is defensible because it reports what is visible and routes the engineering question to someone qualified.
Language and limitations
Describe; don't conclude. "Soft, stained wood at the ledger" is an observation; "the deck is unsafe" is an engineering opinion you were not retained to give. Distinguish "no defects observed" from "not inspected" - never write the first when access was blocked. Note the method (visual, from grade, pick test) so the client understands the depth of the inspection.
Worked example
A 4x4 guard post is notched over the rim and held with two deck screws, with posts spaced 8 feet apart. Report it as a safety concern: notching and screw fastening reduce the post's ability to resist lateral load, and 8-foot spacing exceeds the 6-foot maximum common in deck guidance. Recommend a contractor replace or reinforce the connection with through-bolts or approved brackets.
Traps that cost marks
Exceeding the SOP by declaring structural adequacy; recommending "repair as needed" with no specificity; omitting the limitation statement; and letting a verbal comment substitute for a written report.