Nationwide Property & Appraisal Services

August 8, 2025

From The ValuVault: What Really Counts as Square Footage

Season 3, Episode 13: From The ValuVault: What Really Counts as Square Footage

Square footage sounds simple—grab a tape measure, multiply length by width, done. In reality, the number has rules, exceptions, and big consequences for contracts and appraisals. Misstate it and you can tank a deal when the appraised value falls short.

Below we unpack ANSI Z765, the measurement standard most residential appraisers follow, and show you what does and doesn’t belong in a home’s Gross Living Area (GLA).

ANSI Rule	Why It Matters
Only finished, above-grade space counts	Keeps the “living area” an apples-to-apples comparison across homes.
Spaces must be heated/cooled and finished to the main-house quality	Ensures you’re valuing comparable comfort and utility—not rough storage.
Ceiling height must be ≥ 7 ft (6′ 4″ under beams)	Excludes tight attic nooks that don’t live like real rooms.
Square footage is measured to the exterior walls	Captures the full footprint; interior measurements will understate size.

2. What Doesn’t Count (Even if It Looks Amazing)

Basements & Below-Grade Levels

Beautiful bars, theaters, even bowling alleys 🕹️—it’s still below grade. ANSI separates it from GLA because buyers value subterranean space differently.

Attics

• Must have permanent stairs and 7-foot ceilings in at least half the area.
• Pull-down ladders or sloped ceilings that can’t meet height rules? Exclude.

Garages (Finished or Not)

Insulated drywall and epoxy floors feel “livable,” but garages remain utility space—value them separately.

Enclosed Porches & Sunrooms

They only join the GLA if they’re heated/cooled and finished to the same standard as the rest of the home.

3. Common Measurement Pitfalls

Using MLS or public-record square footage without verification.
Including a basement apartment as GLA in markets that exclude below-grade.
Counting converted carports/bonus rooms that lack permanent HVAC.
Overlooking ceiling-height rules in 1.5-story homes.
Assuming additions are permitted and comparable—city records may disagree.

Mistakes here inflate expectations. When the appraiser corrects the square footage, the contract price can land above market value and trigger renegotiations or cancellations.

4. Role-Specific Guidance

Appraisers

Re-measure when sources conflict.
Flag discrepancies early so agents can address them before underwriting.

Agents & Sellers

Order a certified measurement if the home has complex geometry or prior additions.
Disclose below-grade and non-conforming spaces clearly in listings.

Buyers

Ask which areas are in GLA versus finished but excluded.
Price below-grade or non-conforming space separately when comparing comps.

5. Key Takeaways

GLA = finished, above-grade, ANSI-compliant space.
Basements, low-ceiling attics, garages, and unheated sunrooms stay out.
Accurate measurement prevents appraisal gaps and contract headaches.
When in doubt: measure it out—or hire a pro who will.

Need Help Navigating Square Footage or Valuation?

Nationwide Property & Appraisal Services partners with one of the largest nationwide panels of certified appraisers and measurement specialists. Whether you’re validating MLS data, underwriting a portfolio, or resolving a contract dispute, we’ve got you covered.

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