Home Square Footage Measurement (ANSI Z765) in the Phoenix Metro

County records, old MLS listings, and builder brochures often get a home’s size wrong. In Arizona, where many homes have additions, enclosed patios, converted garages, and casitas, those errors happen a lot. Firebird Appraisals & Consulting measures homes on site following the ANSI Z765 standard and gives you a dimensioned floor plan sketch with the gross living area (GLA) calculated. Gabe Trevizo has been appraising Valley homes since 2005 and holds Arizona license 22146.

Why square footage matters so much here

Most buyers and agents compare Valley homes on price per square foot. If your Chandler home is listed at 2,050 square feet but actually has 2,180 finished, you may be underpricing it. If an enclosed Arizona room was counted as living area when it doesn’t meet the standard, an appraiser for the buyer’s lender can find the discrepancy late in escrow, and that can put the deal at risk.

Common sources of error we see in Maricopa and Pinal Counties:

• Patio enclosures and Arizona rooms that aren’t heated and cooled like the rest of the house or don’t connect to the main living area.
• Garage conversions with a different floor level or no permit history.
• Detached casitas and guest houses. Under ANSI, these are reported separately from the main dwelling’s GLA.
• Areas with low ceilings in lofts and bonus rooms. ANSI sets minimum ceiling heights for finished area.
• Builder or assessor figures that were measured differently, or never updated after a remodel.

What ANSI Z765 measurement means

ANSI Z765 is the American National Standard for calculating square footage in single-family homes. Fannie Mae requires appraisers to use it for appraisals that include interior and exterior inspections. It’s useful because the method is consistent: exterior dimensions, rules for what counts as finished space, ceiling-height minimums, separate reporting for above-grade and below-grade areas, and rounding conventions. When a seller, buyer, and appraiser all use the same method, arguments over square footage tend to go away.

What you get

• An on-site measurement of the home’s exterior, with interior checks where the standard requires them.
• A computer-generated floor plan sketch with dimensions.
• Calculated finished above-grade GLA, plus separate figures for garage, covered patio, and any detached living areas.
• Notes on areas that do not qualify as GLA and why.

Measurement-only work is not an appraisal and does not include an opinion of value. If you also need a value, pair it with a pre-listing appraisal or a non-lender appraisal. The measurement is included in a full appraisal at no extra charge.

Who orders a measurement

• Sellers and listing agents who want an accurate MLS figure before they go live.
• Buyers checking a listing’s square footage during the inspection period.
• Homeowners with additions who want a documented record for insurance or future sale.
• Owners correcting records who need dimensioned documentation to discuss with the assessor’s office. Please note that Firebird does not represent clients in property tax appeals.

Where we measure

We measure homes throughout the Phoenix metro and Pinal County. That includes older block homes in central Phoenix and Tempe, master-planned communities in Gilbert, Queen Creek, and Buckeye, and newer subdivisions in Maricopa and San Tan Valley. Scheduling usually takes about an hour on site for a typical home. Most reports are delivered within five business days.

How to prepare for the measurement visit

Make sure the appraiser can get around the outside of the home. That means unlocked side gates, dogs secured, and a clear path along the side yards, which are often narrow and graveled in Valley subdivisions. Inside, we need to see each room, including any lofts, bonus rooms, and converted spaces. If you have permits, plans, or contractor paperwork for an addition or garage conversion, have them ready. They help explain what we observe. If you know your HOA or builder reported a different figure, tell us. We’ll explain any difference in the report so you can talk about it confidently with buyers, agents, or the assessor.

Most measurement visits take about an hour for a typical single-level home. Larger two-story homes and properties with detached structures take longer.

Frequently Asked Questions

Is ANSI measurement required in Arizona?

Arizona doesn’t require a specific standard for listing square footage. Fannie Mae requires ANSI Z765 for appraisals with interior and exterior inspections, so measuring to ANSI keeps your figure consistent with what a lender’s appraiser will likely report.

Does an Arizona room count as square footage?

Only if it meets the standard for finished living area, which generally means it’s finished like the rest of the house and directly connected to it. Many enclosed patios don’t qualify, and we explain the reason in the report.

Does a casita count toward the home’s square footage?

Under ANSI, a detached casita or guest house is reported separately from the main home’s gross living area. Its value can still be very real, and an appraisal accounts for it separately.

Is a measurement the same as an appraisal?

No. A measurement-only report documents size and layout and doesn’t give a value. If you need a value, order a full appraisal, which includes measurement.

Can you help me appeal my property taxes?

Firebird doesn’t handle property tax appeals or provide expert testimony. You’re welcome to use our measurement report however you choose.

Related: Pre-listing appraisal · New construction appraisal · Non-lender appraisals · Chandler · Scottsdale · Service area