505 East 79th Street (East River House)

The building rises nineteen stories in red brick along the north side of East 79th Street, with a large land parcel — nearly 22,000 square feet — and 260,000 gross square feet above it. The massing is post-war and straightforward; the elaboration is in the balconies and setback terraces, which appear through the upper stock and on the eastern and southern exposures where the river is visible over the low-rise blocks toward East End Avenue.

The apartment mix runs from alcove studios in the low 600-square-foot range through one-bedrooms around 750 square feet and two-bedrooms from roughly 900 to 1,300 square feet, with larger configurations above, per listing records. Birnbaum's planning conventions are present throughout — real entry foyers, defined dining space in the larger lines, and closet counts that renovation-minded buyers routinely underestimate. Compare line position alongside floor here: southern and eastern lines carry the outdoor space and the river outlook; northern and western lines look across the block and require a separate exposure comparison. Combinations exist — DOB filings record at least two apartment combinations, in 2002 and 2005 — which is why the corporation's apartment count and any brokerage unit count may differ slightly.

Full-service and conventionally run: 24-hour doorman, live-in resident manager, three elevators, central laundry, storage and bicycle rooms, and the 24-hour attended garage. The building's DOB record over the past twenty-five years shows repeated facade and masonry campaigns including a Local Law 11 cycle with sidewalk protection in 2017, a boiler replacement with new burners filed in 2015, a fuel-conversion filing, and routine cellar and common-area work. Filings do not confirm completion or current condition; the financial statements and recent engineering reports are the place to confirm those, along with reserve levels and assessment history.

The corporation's debt is visible in the public record: refinancings in 2012 and 2018, and a May 2021 consolidation of roughly $8.1 million with about $2.5 million in new money. The maturity date is the number that matters to a buyer, and it is not public. Ask for it, along with the reserve balance, the current garage lease terms, and any assessment in place or recently concluded.

The team's reviewed materials do not establish every current policy. The board's financing ceiling, minimum down payment, post-closing liquidity requirement, debt-to-income standard, flip tax, sublet policy, pied-à-terre practice, and treatment of trusts, limited liability companies, co-purchasers, guarantors and parental gifting require confirmation in the current governing documents and management's written responses. Do not price an offer against a neighborhood assumption.

Obtain the following in writing from the managing agent before you offer: the maximum permitted financing and minimum down payment; the post-closing liquidity requirement and how the board measures it; whether a flip tax exists and how it is computed; the sublet policy including any ownership seasoning period, term limits and sublet fee; whether pied-à-terre purchases are considered and on what terms; and the board's posture on trusts, LLCs, co-purchasers and guarantors. Then run the Co-op Board Qualification Calculator against the actual figures, not the corridor norm.

Recent sales

Recent transfers at this building, from The Roebling Research Library. Prices are the transfer amounts recorded with the NYC Department of Finance; apartment-level detail is checked against the building’s own file in The Roebling Research Library before publishing.

Market read. Most recent trades (2026 to date) cleared a median $954/sf (floor-adjusted) across 7 sales. Floor-adjusted means each sale is restated to a constant mix of floors, so the figure can differ from the plain median of the sales listed above. Median listing discount 2.9% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.

Sales sourced from NYC Department of Finance recorded transfers (BBL 1-01576-0005). Apartment-level facts (line, condition, asking-price context) curated and cross-verified in The Roebling Research Library. Not all transactions cross-verify with ACRIS records — sponsor and LLC purchases sometimes record at stipulated values rather than market price; square footage on co-ops is not officially recorded, figures shown are approximate.

These are shares, and the board is the gate. You will submit a full board package — financial statement, tax returns, bank and brokerage verifications, employment and personal references — and you will sit for an interview. The package is the transaction. Build it before you are in contract, not after.

Get the financing ceiling and liquidity requirement in writing first. They are unpublished and they are the two numbers most likely to end a deal late. A post-war co-op of this size can sit anywhere from 70 to 80 percent financing, with a post-closing liquidity requirement measured in years of maintenance and mortgage. Assume nothing.

Ask about the garage lease. The garage is the corporation's only commercial income. Its rent, term and renewal date belong in your underwriting, because a below-market lease or an approaching renewal is a maintenance question in disguise.

Ask about the underlying mortgage maturity. The corporation consolidated roughly $8.1 million in May 2021. Find out when it matures and what the board's plan is. Refinancing risk at a 209-unit co-op is manageable, but only if it is known.

Establish the sublet, pied-à-terre and entity rules before you offer. If you need to sublet in five years, or you are buying through a trust or as a second home, that is a threshold question, not a closing detail. Run the Co-op Affordability Calculator once you have the real maintenance and the real financing cap.

Qualify the buyer against the board, not the market. The most expensive outcome here is a signed contract that fails at the board. Screen for liquidity and debt-to-income against the building's actual standards before you accept an offer, and prepare the buyer's package alongside them.

Lead with the outdoor space. Balconies and terraces with river outlook are the building's differentiated product in a corridor where most post-war stock has neither. Photograph them, and market the line rather than the floor.

Document the building's capital work. The facade cycles, the boiler replacement, and the absence of any abatement cliff are all questions a careful buyer's attorney will ask; have records confirming completion and current condition ready. Put the financial statements and the garage lease terms in front of counsel early.

Price the renovation math honestly. Buyers of estate-condition apartments will price the work, and its scope depends on each apartment's current systems and condition. Run the Renovation Cost Calculator against your asking strategy.

If you're considering 505 East 79th Street, also evaluate:

• 515 East 79th Street — the immediate cooperative neighbor on the same tax block; the closest like-for-like comparison
• 510 East 80th Street (The Carriage House) — same block, lot 7501; the condominium alternative for buyers who want deeded ownership and no board approval
• 425 East 79th Street — Yorkville cooperative at similar scale, west of York Avenue
• 440 East 79th Street — post-war cooperative on the same street
• 460 East 79th Street — the York Avenue-adjacent post-war alternative
• 1498 York Avenue — cooperative on the western end of the same block
• 2 East End Avenue and 10 East End Avenue — the East End Avenue corridor's cooperatives at the block's eastern end; the prestige step-up
• 200 East End Avenue — full-blockfront post-war cooperative opposite Carl Schurz Park, with an on-site garage and a comparable operating profile
• 300 East 79th Street — the large alternative further west on the same street
• 525 East 80th Street — Yorkville building one block north