Appraisal Standards · 6 min read

Appraisal Sketch Requirements: UAD and ANSI Standards

If you are completing a UAD-compliant appraisal for Fannie Mae, Freddie Mac, or FHA, your floor plan sketch has specific requirements. Here is what you need to include, what methodology applies, and how PlanSnapper fits into the workflow.

What UAD requires for the sketch

The Uniform Appraisal Dataset (UAD) is Fannie Mae and Freddie Mac's standardized format for residential appraisal reports. UAD does not publish a separate sketch standard — sketch requirements come from ANSI Z765-2021 (the measurement methodology) and from the Fannie Mae Selling Guide (which governs what goes in the report).

For a UAD-compliant appraisal, the sketch must:

• Show a floor plan drawing for each above-grade level of the home
• Include all exterior dimensions with labeled measurements
• Show area calculations for each level (typically in a calculation box or breakdown)
• Clearly identify GLA vs non-GLA areas (garages, porches, below-grade space)
• Be internally consistent — dimensions must add up to the reported square footage
• Use exterior wall measurements per ANSI Z765 methodology

The sketch does not need to be architectural quality. A neat, clearly labeled hand-drawn or software-generated plan is acceptable as long as it is accurate and complete.

ANSI Z765 and exterior measurement

Fannie Mae requires ANSI Z765-2021 for all GLA calculations on conventional loans. Under ANSI, you measure from the exterior face of the exterior walls — not interior wall-to-wall. This means the sketch dimensions reflect the outside perimeter of each floor level.

For a simple rectangular home, this is straightforward: measure all four exterior walls and multiply length by width. For L-shaped, T-shaped, or irregular homes, you break the perimeter into rectangles and calculate each separately. Your sketch should show this breakdown, not just the total.

What is ANSI Z765 explains the full standard and its ceiling height, above-grade, and garage exclusion rules.

What to label in the sketch

Every area in the sketch should be labeled. This includes:

• GLA areas: Label each above-grade finished level with its area (e.g., "First Floor: 1,240 sq ft")
• Garage: Label as "GAR" or "Garage" with its area, clearly excluded from GLA
• Porch / deck / patio: Label and exclude from GLA
• Below-grade finished area: If applicable, label separately as "BGFA" or "Basement" and exclude from GLA
• All dimensions: Each exterior wall segment should have a dimension label

Reviewers and underwriters use the sketch to verify that your reported GLA is mathematically supported by the dimensions shown. If your dimensions do not add up to your reported number, expect a Collateral Underwriter flag or a revision request.

Common sketch errors that trigger revision requests

• Dimensions that do not close: The sum of wall segments along one axis does not match the opposite side. The sketch is geometrically impossible and the area calculation cannot be verified.
• Interior measurements instead of exterior: If you measure interior room widths and add wall thickness manually, you introduce rounding error. Measure the exterior perimeter directly.
• Garage included in GLA: An attached garage with dimensions shown but not clearly excluded is a common audit trigger.
• Missing calculation breakdown: Showing only the final GLA number without a level-by-level or room-by-room breakdown is insufficient for complex properties.
• Inconsistent rounding: ANSI Z765 calls for rounding to the nearest whole square foot. Reporting 1,247.3 sq ft on the form and 1,247 in the calculation box creates a minor discrepancy that some review systems flag.

Sketch software and PlanSnapper

Most appraisers use sketch software like SketchPad, APEX, or the built-in sketch tool in their ACI, a la mode, or Bradford Technology platforms. These tools generate a labeled floor plan with area calculations built in, and they export directly into the appraisal report.

PlanSnapper serves a different but complementary role. It calculates accurate GLA from an existing floor plan image — a CubiCasa export, a builder floor plan, an MLS attachment, or a scanned handout. If you have a floor plan but need to verify or quickly calculate the GLA before entering it into your sketch software, PlanSnapper gives you the number in under two minutes.

This is useful for efficiency: measure with PlanSnapper first, then build your sketch in your appraisal platform. It is also a cross-check tool — if your sketch software is giving you a number that does not match your field notes, PlanSnapper lets you verify from the floor plan independently.

See Can PlanSnapper replace field measurement? for a direct answer on where it does and does not substitute for a field sketch.

FHA and VA sketch requirements

FHA does not require ANSI Z765 but expects the sketch to support the reported GLA using a consistent and documented methodology. VA appraisals follow similar guidance. In practice, using ANSI Z765 for FHA and VA appraisals is accepted — the standard is more rigorous than what these agencies require, so there is no conflict.

For manufactured homes, HUD has specific measurement guidelines that differ from ANSI. See How to measure a manufactured home for details.