Do appraisers follow ANSI Z765 when measuring condos?

Yes. ANSI Z765 applies to condo appraisals for federally backed loans. The standard specifies that for attached units, measurement is taken from the interior face of the exterior walls. This differs from the exterior-dimension method used for detached single-family homes.

How do I verify a condo's square footage before buying?

Request the appraisal from the listing, check the tax assessor record, and review the HOA disclosure documents. You can also upload a floor plan from the listing to a browser-based tool like PlanSnapper to get an independent square footage estimate before making an offer.

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Appraisal Standards

Part of: How to Measure Square Footage: The Complete Guide

How to Measure Condo Square Footage for an Appraisal

Condo measurement is different from single-family measurement in one fundamental way: you usually cannot measure the exterior walls. Here is how ANSI Z765 applies to condos and how to get accurate, defensible square footage on a 1073 form.

The Core Challenge with Condos

ANSI Z765 requires measuring from the exterior walls of a dwelling. For a single-family home, that means walking the perimeter and recording outside dimensions. For a condo unit, the exterior walls are shared with neighboring units or building common areas. You cannot measure them from the outside in any practical sense.

ANSI Z765 addresses this by allowing interior measurement for attached units where exterior measurement is not feasible. The standard permits wall-to-wall interior measurement as a substitute, with the understanding that this will produce a slightly smaller figure than exterior measurement (by the thickness of the perimeter walls).

Three Measurement Methods for Condos

Method	How It Works	Best For
Wall-to-wall interior	Measure interior face to interior face; excludes wall thickness	Consistent with most condo market comps
Centerline of shared walls	Halfway through shared walls; interior face of exterior walls	Attached townhomes more than high-rise condos
Floor plan tracing	Scale architectural plan; trace unit boundaries	High-rise units where field comp access is limited

Appraisers use several approaches depending on what is accessible and what the comparables are based on:

Wall-to-wall interior. Measure from interior wall face to interior wall face. Consistent and reproducible. Does not include wall thickness. Used in many condo markets as the de facto standard.
Centerline of shared walls. Measure to the centerline of shared walls (halfway through the wall) and to the inside face of exterior walls. Attempts to split the wall thickness with adjacent units. More common in attached townhome appraisals than high-rise condos.
Floor plan tracing. Many condo buildings have architectural drawings or unit plans that show interior dimensions or are to-scale. Tracing from a to-scale plan and setting scale from a known dimension is often the most practical approach for high-rise units where field access to multiple comparable units is not available. See the floor plan scale calculator guide for how to set scale from a known wall dimension.

The most important rule is consistency: whatever method you use for the subject, use the same method for your comparables. If the market is accustomed to wall-to-wall interior measurement and you report exterior-equivalent GLA, your numbers will not align with market data.

What the 1073 Form Requires

The 1073 (Individual Condominium Unit Appraisal Report) has a GLA section similar to the 1004.Fannie Mae and Freddie Mac require ANSI Z765-compliant measurement on the 1073 as well, using the interior method where exterior measurement is not feasible.

The form also asks for project-level information including total units, units for sale or rent, and project amenities. The square footage reported is unit-level GLA only, not including balconies, storage units, or common areas. The appraisal sketch addendum must accompany the 1073 and show the measured unit footprint with labeled dimensions.

Balconies, Storage, and Parking

Outdoor balconies and terraces do not count as GLA regardless of how they are finished. They contribute value as amenities and should be described in the appraisal, but they are not included in the square footage total.

Enclosed balconies that are heated and cooled, accessible from the interior, and meet ceiling height minimums present a judgment call. If they were converted to enclosed living space as part of the original construction or a permitted renovation, they may qualify for GLA inclusion. If they were informally enclosed by a prior owner, they typically do not, and may raise condition or permitting issues.

Storage units and parking spaces are separate from GLA. They have their own contributory value and should be addressed in the addendum if they are non-standard for the project.

Using Floor Plans for Condo Measurement

Many condo buildings make unit floor plans available through the HOA, building management, or the developer's website. Older buildings may have architectural drawings available through the county. MLS listings for condo units increasingly include to-scale floor plans generated by services like CubiCasa or iGUIDE.

If you have a to-scale floor plan, you can trace the unit perimeter digitally and set scale from any wall whose dimension you have verified in the field. This approach works especially well for high-rise units where the exterior is not accessible and the floor plan matches the actual unit layout. Save the traced measurement with the plan image as part of your work file.

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Upload a unit floor plan, trace the interior perimeter, verify scale against one known wall dimension, and get accurate GLA in under two minutes. Works for any unit layout.

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Frequently Asked Questions

How is condo square footage measured?

Condos can be measured using three different standards: interior (drywall to drywall), exterior (outside of exterior walls), or drip line (centerline of shared walls). The method varies by state, building, and HOA. Always confirm which standard applies before comparing units.

Why do condos often list different square footage figures?

Different measurement standards produce different numbers for the same unit. Interior measurements exclude wall thickness; exterior measurements include it. Some listings use the developer's marketing figure, which may not match an ANSI or appraiser measurement.

Does condo square footage include shared spaces?

No. GLA for a condo unit counts only the space within the unit itself. Common areas like lobbies, hallways, gyms, and parking garages are not included in individual unit square footage, even though owners have access to them.

What is the difference between interior and exterior condo square footage?

Interior measurement counts from the inside face of enclosing walls, excluding wall thickness. Exterior measurement includes wall thickness. Fannie Mae ANSI Z765 guidance for condos (form 1073) requires interior measurement — the opposite of the single-family standard, which uses exterior walls.

Is HOA-reported square footage reliable for appraisals?

HOA-reported square footage is often taken from building plans and may not reflect as-built dimensions or current ANSI standards. Appraisers are required to independently verify or measure condo square footage rather than relying solely on HOA records.

Does a condo balcony count toward square footage?

No. Balconies, terraces, and patios are not included in GLA under ANSI Z765. They may be noted as additional features and adjusted for value, but they do not add to the interior living area reported on the appraisal form.

Why might two appraisers report different square footage for the same condo?

Condo measurement can vary because of inconsistent treatment of where walls begin and end, inclusion or exclusion of closets and mechanical spaces, and whether the appraiser measured independently or relied on building records. ANSI Z765 standardizes the method, but pre-2022 appraisals may reflect older practices.

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