Anthony Licciardello | May 13, 2026
Staten Island
The 2026 Staten Island Basement Report
A recent Prodigy listing tour — 7 Whitehall Street, Oakwood — a custom-built brick home where the lower level meaningfully shapes total value, exactly the dynamic ANSI now reports separately on the appraisal.
By Anthony Licciardello, The Prodigy Team · Published May 12, 2026 · 9 min read
✦ Key Takeaways
If you've ever looked at the appraisal on a Staten Island home and thought, "Where did the rest of my square footage go?" — you're not imagining it. On April 1, 2022, Fannie Mae mandated a national measurement standard called ANSI Z765-2021. Freddie Mac followed in November 2023. The rule changed how every appraiser in the country reports the size of a home, and on Staten Island — where finished basements, high ranches, and mother-daughter setups define entire neighborhoods — the financial consequences are real.
The short version: under ANSI, if even one fraction of a level sits below the exterior grade of the earth, that entire level is reported as basement area — not as Gross Living Area (GLA). It doesn't matter how beautifully it's finished, whether it has full-size windows, or whether it walks straight out to your backyard. On the report, it shrinks.
But the market — the actual buyers writing offers on Staten Island in 2026 — doesn't read appraisal reports the way appraisers do. Sold data from SIBOR (Staten Island Board of Realtors) tells a different story: finished, permitted basement space adds $25,000 to $75,000 to the sale price of a typical Staten Island home, and homes with finished basements consistently sell 15–20% faster than comparable homes without them. The gap between what ANSI counts and what the market pays is where pricing strategy lives.
The Regulatory Shift
Before April 1, 2022, residential appraisers in the United States operated with a surprising amount of latitude. Different appraisers measuring the exact same home could and did report square footages that varied by more than 10%. For a $750,000 home in Eltingville, a 10% measurement disagreement could translate into a $75,000 swing in price-per-square-foot comparables.
Fannie Mae's adoption of the ANSI Z765-2021 standard was meant to fix that. The standard establishes one professional, defensible method for calculating GLA — and one absolute rule that has reshaped how Staten Island homes are reported: any level with even a fraction of its floor area below the exterior grade is classified as basement, not living area. Period.
This rule is binary. It applies regardless of finish quality. It applies regardless of whether the windows are full-size. It applies regardless of whether the space walks out to the yard. And it produces what homeowners experience as the "shrinkage effect" — a perfectly nice 2,400-square-foot home that suddenly appears on an appraisal as 1,600 square feet of GLA plus 800 square feet of basement.
▲ The Binary Rule
If any portion of a floor level is below the exterior grade of the surrounding earth, the entire level must be reported as basement area under ANSI Z765-2021. There is no partial credit. There is no walk-out exemption. There is no "but the windows are full-size" provision. The standard is absolute and applies to every detached single-family home and townhouse in the country.
The Staten Island Reality
Staten Island, more than almost any other market in the New York metro, was built around homes where below-grade space is functional living space. High ranches dominate New Dorp and Great Kills. Mother-daughter setups define entire blocks of Eltingville. Townhouse complexes like Village Greens were architecturally designed around full finished basements that buyers in those complexes have always treated as primary square footage.
Under ANSI, none of that space contributes to GLA. The appraisal report separates it cleanly: above-grade GLA in one column, basement area in another. The two numbers don't add. They can't.
But buyers on Staten Island are not appraisers. The market reads the property listing, walks the home, sees a finished family room with high ceilings and a wet bar — and prices accordingly. The result is a structural tension in every Staten Island transaction with a meaningful basement: the market value reflects the basement; the appraisal size does not. Sellers who don't understand this disconnect leave money on the table. Sellers who do understand it — and price, market, and stage the basement appropriately — capture every dollar of the premium.
"On a Staten Island appraisal, the basement is a separate column. In a Staten Island bidding war, it's the column that wins the offer."
— Anthony Licciardello, Broker-Owner, Prodigy Real Estate
One important exception: ANSI Z765-2021 applies to detached single-family homes and townhouses. Apartment-style condominiums continue to follow the long-established interior perimeter measurement method, which is why a one-bedroom condo in a high-rise reads cleanly on an appraisal regardless of where it sits in the building. For Staten Island, this distinction matters most in mixed product complexes — and we'll cover the townhouse implications in detail in Post 4 of this series.
The Premium Math
Because ANSI removes basement square footage from the GLA calculation, Staten Island appraisers use dollar-amount adjustments rather than per-square-foot multipliers to credit the contributory value of below-grade space. That's a critical mechanical detail. When an appraiser compares your home to recent sold comparables, the line item for "finished basement" carries a fixed dollar adjustment — and on Staten Island in 2026, that adjustment typically falls in a defined range.
The range exists because not all finished basements are created equal. A small partially-finished rec room in Mariners Harbor doesn't get the same adjustment as a fully permitted finish in Eltingville with a separate entrance, full bath, and a Letter of Completion on file with the NYC Department of Buildings. The table below maps how SIBOR-environment appraisers typically tier the adjustments based on sold data through Q1 2026.
| Basement Condition | Value Adjustment | DOM Impact |
|---|---|---|
| Unfinished (raw) | $0 – $5,000 | Normal (70–75 days) |
| Partially finished | $10,000 – $25,000 | Normal (~70 days) |
| Finished & permitted | $25,000 – $75,000 | 15–20% faster |
| Legal two-family conversion (new C of O) | $50,000 – $100,000+ | Different product class |
Source: SIBOR sold data through Q1 2026; Prodigy Real Estate market adjustments file. Note: A mother-daughter home is, by NYC definition, a single-family Certificate of Occupancy with an internal layout that supports multi-generational living — the premium comes from functional utility, not from a special C of O. A "legal two-family conversion" is a separate product class with its own multi-family C of O. The Post 3 analysis in this series covers the mother-daughter layout premium in detail.
The marketwide resale lift for a finished basement versus an otherwise comparable home with an unfinished one — roughly $60K to $90K on a $750,000 Staten Island home, which lines up almost exactly with appraiser line-item adjustments.
The 8% to 12% headline number is the marketwide aggregate. The two metrics — per-line-item adjustment and aggregate resale lift — reinforce each other, which is why appraisers and listing agents on Staten Island treat them as the same conversation.
For Sellers in 2026
If you're preparing to sell a Staten Island home with meaningful below-grade space in 2026, ANSI changes three things about how you should think about pricing and marketing.
First, the listing presentation matters more than ever. Because the basement won't carry the appraisal weight of upstairs square footage, the buyer's emotional and financial connection to the space has to be established during the listing experience. Photos, video tours, staging, and copywriting all have to communicate the basement as a primary living area — not an afterthought. This is where the Prodigy in-house 4K listing video studio carries weight; cinematic tours that walk a buyer through a finished basement the same way they walk through a primary suite shift the perceived value before an appraiser ever opens the report.
Second, the legal status of the finish becomes a pricing lever. A finished basement with a valid certificate of occupancy and permits on file appraises and sells for 15% to 20% more than an identical non-permitted finish. We cover the C of O pathway in detail in Post 6 of this series — but if you're sitting on a non-permitted finished basement, that conversation needs to happen before the listing photos do.
Third, the days-on-market math reinforces every other decision. Finished basements don't just sell for more; they sell faster. The 15–20% DOM reduction is the most consistent pattern in Staten Island sold data for 2025–2026. In an inventory-deficit market — which we remain in through mid-2026 — speed-to-clearing-price is the entire game. Listings that close in 14 to 21 days don't have time to develop the price-reduction overhang that drags long-DOM properties down by 3% to 5%.
The Series Map
This anchor post sets the framework. The next five posts go deep on the specific market segments where below-grade value is most consequential on Staten Island:
✦ Thinking About Selling in 2026?
Before you list, the legal status, finish quality, and marketing strategy for your below-grade space should all be settled. A 20-minute pre-listing conversation usually identifies the one or two decisions that move the number the most. No pressure, no listing pitch — just a clear read on where your basement sits in the 2026 SIBOR adjustment range.
Call (718) 701-5626 Request a Basement Audit →
Anthony Licciardello · The Prodigy Team · Conversations are confidential.
Frequently Asked Questions
Does my finished walk-out basement count as living space on the appraisal?
No. Under ANSI Z765-2021, if even one fraction of a level is below the exterior grade of the earth, the entire level is reported as basement area, not Gross Living Area. Walk-out access, full-size windows, and high-end finishes do not change the classification on the appraisal report. They do, however, materially affect the dollar-amount adjustment the appraiser applies — and they significantly affect the market price the home will command from buyers.
How much does a finished basement actually add to my Staten Island home value?
SIBOR sold data through Q1 2026 shows finished, permitted basement space adds $25,000 to $75,000 to the typical Staten Island single-family home sale price — roughly an 8% to 12% lift over a comparable home with an unfinished basement. The high end of the range applies to fully permitted, code-compliant finishes with a Letter of Completion (or amended C of O for the finishes) on file with the NYC Department of Buildings. Homes that are legally converted to a two-family with a new multi-family C of O sit in a different — and typically higher — product class altogether. Mother-daughter homes, which are single-family C of Os with multi-generational layouts, command their own layout-based premium that we cover in Post 3 of this series.
Why does my appraisal show less square footage than my listing did?
This is the most common ANSI question we hear on Staten Island. Pre-2022 listings frequently combined above-grade and below-grade space into a single total square footage figure. Under ANSI, an appraiser is required to separate those two numbers — and the basement area, no matter how nicely finished, no longer rolls up into GLA. The home didn't change. The reporting standard did. Sellers who understand this can address it head-on in listing copy and buyer conversations, instead of letting it become a surprise late in the deal.
Do these ANSI rules apply to condos and townhouses on Staten Island?
Apartment-style condominiums are measured using the interior perimeter method, which is unchanged by ANSI Z765-2021. Townhouses, however, are explicitly covered by the standard and follow the same below-grade rule as detached single-family homes. This is why townhouse complexes with finished basements — like Village Greens in Arden Heights — show pricing patterns that closely mirror detached single-family markets, while slab-foundation townhouses without below-grade space trade in a meaningfully lower band.
Should I finish my basement before listing, or sell as-is?
It depends on three variables: the current condition, the neighborhood, and the timeline. In high-demand South Shore neighborhoods like Great Kills, Eltingville, and Annadale, finished basements are an expected amenity — unfinished space often costs you both price and days on market. In lower-median neighborhoods, the renovation math may not recover. A pre-listing audit identifies which path returns the most, accounting for permits, finish budget, and current market depth. Post 2 of this series walks through the ROI calculation in detail.
Sources & Methodology
Fannie Mae Single Family Standardized Property Measuring Guidelines (ANSI Z765-2021 adoption, effective April 1, 2022); Freddie Mac ANSI Z765 adoption (November 2023); SIBOR Q1 2026 closed-sale data; Appraisal Institute commentary on Fannie Mae's adoption of ANSI standards; Prodigy Real Estate internal market adjustments file (Richmond County, 2025–2026).
Prodigy Real Estate is an innovative real estate company offering high-end video production, home valuation services, purchasing, and home sales. Serving New York and New Jersey.