UAD1777 — Provide the 'Finished Area Below Grade (Nonstandard)' for the sales comparable, even if the value is 0.

Where this rule lives in the report

Report Section and Report Subsection as the GSEs define them — the black tab and grey bar you already read on the URAR.

1. 01Open the Sales Comparison Approach › Unit(s) › Finished Area Below Grade (Nonstandard) area of the URAR and find Finished Area Below Grade (Nonstandard).
2. 02Check the condition that triggers UAD1777: (@ValuationUseType = "SalesComparable" or @ValuationUseType = "SubjectProperty") and (ImprovementType = "Dwelling" or (ImprovementType = "Outbuilding" and OutbuildingRealPropertyIndicator = "true" and AccessoryDwellingUnitIndicator = "true")) and ((UnitNonStandardBelowGradeFinishedAreaMeasure > 0 for @ValuationUseType = "SubjectProperty") and UnitNonStandardBelowGradeFinishedAreaMeasure is not provided in the comparable instance of PROPERTY_UNIT_AREA that was compared with the subject unit).
3. 03Review and correct the value when appropriate; this is a Warning, but it can still raise reviewer questions.
4. 04Use the official Single-family (SF1) sample value on this page as a reference pattern, then re-run validation.

This fix guidance is derived from the published rule message, trigger logic, report location, field definition, and official sample data available for this rule.