235 West End Avenue (The Gemstone)
235 West End Avenue, New York, NY 10023
Lincoln Square, Upper West Side
BBL 1011827501 · BIN 1076239
- Year built
- 1928
- Type
- Condominium
- Units
- 143
- Floors
- 17
- Landmark
- No
- Pets
- Pet-friendly (verify current house rules at offer stage)
- Subletting
- Permitted under the condominium declaration
- Pied-à-terre
- Allowed
Every recorded sale at this building, 2002–2026
Price-per-square-foot over time, the line- and floor-premium curves, and every recorded sale.
- Median $/sf
- $1,229
- Listing discount
- 2.3%
- Recorded sales
- 153
- On record
- 2002–2026
The Gemstone is a Bing & Bing prewar — and that pedigree is the anchor of everything the building offers. The Bing brothers were the most respected apartment-house developers of 1920s Manhattan, and their buildings are prized for the quality of their construction, the generosity of their room proportions, and the discipline of their layouts. What makes 235 West End Avenue distinctive within that body of work is its condominium structure: a prewar Bing & Bing building that trades as a condominium rather than the cooperative form nearly universal among its peers.
That distinction is decisive for a certain buyer. Prewar West End Avenue and Riverside Drive are overwhelmingly cooperative — pedigreed, but governed by board interviews, financing caps, and sublet limits. The Gemstone delivers the prewar architecture, the West End Avenue address, and the Medieval Revival character in a condominium wrapper: financing flexibility, pied-à-terre eligibility, and closings that run on condominium timelines. Prewar bones, condominium mechanics — an uncommon pairing on this stretch of the Upper West Side.
Architecture and unit composition
Bing & Bing's 1928 commission is a seventeen-story Medieval Revival prewar in brick, with limestone and terra-cotta ornament concentrated on the lower stories. The entry is distinguished by stained-glass casement windows, and the lobby carries colorful ceramic-tile detailing on the staircases — the kind of period craftsmanship that defines the building's character.
The residences reflect the building's prewar planning: generous room dimensions, formal layouts, and the solid construction the Bing name implies. The original 184 apartments have, over the decades since the 1987 conversion, been partially combined into roughly 143 units, producing a mix that ranges from prewar one-bedrooms to larger combined layouts. Condition varies line by line with renovation history.
Building operations
The Gemstone operates as a full-service condominium with a 24-hour doorman and a live-in resident manager. Amenities include a fitness center, central laundry, a children's playroom, a landscaped roof deck, and bike storage. The building is pet-friendly.
The 1987 conversion places the building in the wave of prewar rental-to-condominium conversions on the Upper West Side. Common charges and property taxes are consistent with a full-service prewar condominium; buyers should model the full carry at the apartment level and review current financial statements, board minutes, and any reserve study during due diligence.
Local Law 97
- 2024–2029 annual penalty
- $0 (under cap)
- 2030–2034 annual penalty
- $33,767/yr
- Per unit / month range
- $0 – $19
Facade safety — Local Law 11
The latest available filing classified the facade as SWARMP — Safe With A Repair and Maintenance Program: the engineer identified conditions requiring monitoring or repair before the next inspection cycle. The scope, timeline, and how the building funds the work are building-specific — we review the filings and board materials for you.
QEWI = Qualified Exterior Wall Inspector — the licensed engineer the city requires to sign the report (the independent expert, not the managing agent). Source: NYC DOB facade filings (FISP) · The Roebling Research Library.
See the full facade history →Recent sales
The Gemstone trades on the strength of two features that rarely appear together on West End Avenue: prewar Bing & Bing architecture and condominium ownership. Pricing is best read on a price-per-square-foot basis, with the condominium structure itself functioning as a premium input against the cooperative inventory that dominates the corridor. Within the building, value is driven by exposure, floor height, room proportion, and renovation condition. Apartment-level closing detail should be sourced from public records for full transactional context, and pricing should be validated against the most recent comparable sales at the time of offer.
Recent closings at this building, curated by The Roebling Team research desk. Apartment-level facts are independently verified before publishing; sale prices reflect the recorded transfer amount at the NYC Department of Finance.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Apr 8, 2026 | 15E | 1 BR · 1 BA · 678 sf | $850,000 | $1,254/sf | -5.0% |
| Sep 25, 2025 | 8D | 1 BR · 1 BA · 777 sf | $885,000 | $1,139/sf | -6.8% |
| Aug 5, 2025 | 16A | 1 BR · 1 BA · 675 sf | $795,000 | $1,178/sf | +0.0% |
| Aug 12, 2024 | 6J | 2 BR · 2 BA · 1,059 sf | $1,695,000 | $1,601/sf | +0.0% |
| Jul 10, 2024 | 8B | 1 BR · 1 BA · 732 sf | $710,000 | $970/sf | -18.9% |
| Feb 16, 2024 | 4D | 1 BR · 1 BA · 778 sf | $840,000 | $1,080/sf | -4.0% |
| Feb 13, 2024 | 6H | 2 BR · 2 BA · 859 sf | $999,000 | $1,163/sf | -9.2% |
| Dec 12, 2023 | 6A | 1 BR · 1 BA · 675 sf | $760,000 | $1,126/sf | -3.7% |
Market read. Most recent trades (2026) cleared a median $1,229/sf across 1 sale. Median listing discount 2.3% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.
The retrade record
Lines that have traded more than once in the public record — the building’s appreciation arc, apartment by apartment.
Full closing history with price-per-square-foot over time, the complete retrade record, and every line that has traded.
Sales sourced from NYC Department of Finance recorded transfers (BBL 1-01182-7501) and verified listing data. Apartment-level facts (line, condition, asking-price context) curated and cross-verified by The Roebling Team research desk. Not all transactions cross-verify with ACRIS records — sponsor and LLC purchases sometimes record at stipulated values rather than market price; square footage from recorded condo declarations and offering plans.
What to know if you’re buying
The Bing & Bing pedigree is real institutional context. The developer's reputation for construction quality and room proportion is a durable value anchor.
Condominium ownership is the differentiator. Financing flexibility, pied-à-terre eligibility, and subletting are governed by the condominium rather than a cooperative board — uncommon for a prewar building on this stretch. Closings run on condominium timelines.
Layout varies with combination history. Because original apartments have been partially combined, room counts and configurations differ meaningfully by line. Verify the specific apartment during walkthrough.
Model the full carry. Common charges plus property taxes plus utilities at the apartment level.
Verify board policy at offer stage. Confirm pet, sublet, and pied-à-terre specifics against the current house rules.
What to know if you’re selling
Lead with prewar-condominium rarity. The pairing of Bing & Bing prewar architecture with condominium ownership is the story that widens the buyer pool beyond what a cooperative peer can reach.
Emphasize the period detail. The stained-glass entry, tiled lobby staircases, and generous room proportions are marketing assets specific to the building.
Pricing requires apartment-level context. Comparable sales vary by line, floor, exposure, and combination history.
Closing timelines are condo-fast. 30 to 60 days from contract to closing.
Comparable buildings
If you're considering 235 West End Avenue, also evaluate:
- 320 West End Avenue — Rosario Candela 1924; nearby West End Avenue prewar peer
- 470 West End Avenue (The Belvoir) — Emery Roth 1928; nearby West End Avenue peer
- 535 West End Avenue — 2011; nearby West End Avenue condominium peer
- 243 West End Avenue (Coliseum Plaza) — Emery Roth 1925; nearby West End Avenue peer
- 100 Riverside Drive — Boak & Paris 1938; nearby Riverside Drive peer
The neighborhood
For the full corridor — architecture, schools, transit, and pricing across West End Avenue — read The Roebling Team Guide to West End Avenue.
Considering a move at The Gemstone?
Request a private building brief with the relevant comparable sales, current and off-market availability, and an apartment-specific view of value.
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at The Gemstone would likely sell for today, what it costs to sell, and what you’d walk away with — reviewed personally against condition, exposures, renovation quality, and the competition actually on the market.