30 Main Street (The Sweeney Building)
30 Main Street, Brooklyn, NY 11201
DUMBO, Brooklyn
BBL 3000367501 · BIN 3335867
- Year built
- 1908
- Type
- Condominium
- Units
- 85
- Floors
- 11
- Landmark
- Designated
- Pets
- Governed by the condominium's house rules; confirm during diligence
- Pied-à-terre
- Allowed
Every recorded sale at this building, 2004–2026
Price-per-square-foot over time, the line- and floor-premium curves, and every recorded sale.
- Median $/sf
- $1,124
- Listing discount
- 3.5%
- Recorded sales
- 133
- On record
- 2004–2026
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at The Sweeney Building 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.
The Sweeney Building is the middle chapter of DUMBO's conversion story — after the Clock Tower proved the market in 1998 and before 70 Washington scaled it in 2005, Two Trees converted the 1908 factory at Main and Water Streets into the neighborhood's second generation of lofts, with the condominium declaration recorded in December 2002 and closings following from 2003. In the neighborhood's now-standard division between authentic industrial conversions and new-development condominiums, the Sweeney occupies the position many buyers end up wanting most: true daylight-factory bones, boutique scale, and the shortest walk to Brooklyn Bridge Park of any conversion in DUMBO.
The building's industrial history broadens the Gairville narrative. Unlike its neighbors at 1 Main and 70 Washington — both built for Robert Gair's paper-box empire by the Higginson/Turner team — 30 Main Street was erected in 1908 by the Moyer Engineering & Construction Company for the W. H. Sweeney Manufacturing Company, a Brooklyn metalware maker. It belongs to the same pioneering generation of reinforced-concrete factory construction that made DUMBO nationally significant: concrete frames carrying the loads, window bays opened wide for daylight, and — in the Sweeney's case — a façade whose concrete piers are articulated to imitate rusticated stone, the detail the LPC's designation report singles out. The result is a factory that dressed its engineering in civic clothes a full decade before that became conventional.
The conversion gave DUMBO some of its most livable lofts: high ceilings, oversized industrial window bays, and floor plates scaled so that typical units get corner or multiple exposures rather than bowling-alley depth. Upper floors carry the exposures that define the neighborhood's imagery — the Brooklyn Bridge to the west, the Manhattan Bridge to the east, the skyline across the river — and the penthouse tier at the top of the building trades as trophy product when it trades at all.
Position completes the argument. The building sits one short block from the Main Street entrance to Brooklyn Bridge Park, across the intersection from the Clock Tower, in the heart of the DUMBO Historic District (designated December 18, 2007). Within the conversion tier, the Clock Tower has the iconography, 70 Washington has the scale and liquidity, and the Sweeney has the park.
Architecture and unit composition
The Sweeney is an 11-story Industrial Neoclassical daylight factory on a corner site, which matters more than it sounds: corner siting means two full window façades, and in a concrete-frame building with oversized bays, that translates directly into the light and view volume that loft buyers pay for. The rusticated-stone articulation of the piers gives the building a more finished street presence than most of its factory peers.
The 85 residences run from one-bedroom lofts through three-bedroom corner spreads and a penthouse tier. Characteristic attributes: ceilings in the high-and-genuinely-lofty range, oversized multi-pane windows, and the concrete structure expressed in many interiors. Because the building is boutique-scale, most lines exist in small numbers — which supports pricing on scarcity but thins the comparable set for any given unit type.
Published unit counts for the building vary slightly (city records tabulate 85; some published counts run a few units higher, reflecting combinations and penthouse configurations over the years). The offering plan and recorded declaration control, and The Roebling Research Library maintains the reconciliation.
Building operations
The Sweeney operates as a serviced boutique condominium — attended lobby service, fitness room, and common roof terrace are the publicly documented amenity set. Two Trees Management Co. was associated with the building from conversion; current management should be confirmed with the board during diligence, and The Roebling Team remains the contact of record for clients. As with every building inside the DUMBO Historic District, exterior and window work requires LPC approval, and buyers should review the current Local Law 11 cycle and capital plan as part of standard diligence at a 1908 concrete structure.
Local Law 97
- 2024–2029 annual penalty
- $0 (under cap)
- 2030–2034 annual penalty
- $27,080/yr
- Per unit / month range
- $0 – $27
Source: NYC LL84 benchmarking and PLUTO · The Roebling Research Library. City record last verified September 2026.
See full Local Law 97 analysis — emissions history, scenarios, methodology →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.
How to read this, and where it comes from
QEWI = Qualified Exterior Wall Inspector — the licensed engineer the city requires to sign the report (the independent expert, not the managing agent).
Penalties shown are amounts DOB assessed against filings on record across 2005–10 to 2020–25. The FISP dataset does not record whether they were paid, contested or remain open, so treat the figure as history rather than a current balance and confirm the building’s standing with the managing agent.
Source: NYC DOB facade filings (FISP) · The Roebling Research Library. City record last verified September 2026.
Recent sales
Recent closings at this building, curated by The Roebling Team research desk. 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.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Aug 24, 2026 | 10D | 1 BR · 2 BA · 1,494 sf | $1,725,000 | $1,155/sf | -1.4% |
| Jul 23, 2026 | 8H | 1 BR · 2.5 BA · 1,230 sf | $1,800,000 | $1,463/sf | +1.4% |
| Jun 8, 2026 | 11F | 2 BR · 2.5 BA · 2,209 sf | $3,623,000 | $1,640/sf | -3.4% |
| May 12, 2026 | 9D | 1 BR · 2 BA · 1,494 sf | $1,825,000 | $1,222/sf | -1.4% |
| Apr 30, 2026 | 2H | 2 BR · 2.5 BA · 2,046 sf | $2,050,000 | $1,002/sf | -6.8% |
| Mar 31, 2026 | 4G | 1 BR · 2.5 BA · 2,556 sf | $2,300,000 | $900/sf | -3.6% |
| Mar 10, 2026 | 3B | 3 BR · 2.5 BA · 1,887 sf | $2,875,000 | $1,524/sf | -0.7% |
| Feb 25, 2026 | 7H | 1 BR · 2 BA · 1,320 sf | $1,590,000 | $1,205/sf | -11.4% |
Market read. Most recent trades (2026) cleared a median $1,124/sf across 8 sales. Median listing discount 3.5% 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 3-00036-7501) 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
This is the park-side authentic loft. One short block to Brooklyn Bridge Park's Main Street entrance — the strongest everyday-location argument in the DUMBO conversion tier.
The bones are the value. A 1908 Moyer-built reinforced-concrete daylight factory with rusticated-concrete façade detail, inside the DUMBO Historic District; the window scale and ceiling volume are original and unreproducible.
Boutique scale cuts both ways. Eighty-five units means intimacy and scarcity value, but a thin comparable set and a smaller amenity budget than the large conversions; review financials with that scale in mind.
Condominium flexibility applies. Right of first refusal rather than board approval; LLC and trust ownership available; 30–45 day closing pacing typical.
Confirm the paper. Amenity details, house rules, and any transfer-fee provisions should be verified against the offering plan and amendments — The Roebling Research Library maintains the file.
What to know if you’re selling
Sell the location first. Park adjacency plus historic-district context is the pairing that distinguishes the building within the conversion tier — lead with it.
Price on scarcity, carefully. Intermittent supply supports premium positioning, but thin comparables mean over-asks sit; anchor to the most recent same-tier conversion closings across the Clock Tower, 70 Washington, and 168 Plymouth as well as building history.
Corner exposures and bridge views photograph the building's argument. Marketing should be built around light and the specific view envelope.
Prepare diligence materials early. A 1908 structure in a historic district will draw LL11 and capital-plan questions; a clean package protects pricing.
Comparable buildings
If you're considering The Sweeney Building, also evaluate:
- The Clock Tower (1 Main Street) — the neighboring founding conversion; the icon across the intersection
- 70 Washington Street — the large-scale Gair conversion; deeper liquidity, same pedigree school
- 168 Plymouth Street — the newest boutique conversion; comparable scale, newer finishes
- Kirkman Lofts (37 Bridge Street) — boutique conversion on the quieter eastern seam of the neighborhood
- 205 Water Street — boutique contemporary condominium alternative in east DUMBO
- 133 Water Street — small modern condominium mid-neighborhood
- 98 Front Street — the new-development counterpoint at mid-scale
- One Brooklyn Bridge Park (360 Furman Street) — warehouse-scale conversion directly in the park, in neighboring Brooklyn Heights
How to read the facts on this page. Items attributed to an offering plan describe the building as it was offered at that filing — unit mix, square footage, the amenity program as planned. They are not a statement about how the building operates today. Tax and compliance figures are sourced separately to current City records and carry their own dates. House rules, staffing and fee policy can change by board resolution without any public filing: treat every policy line here as a starting point for diligence and confirm it with the managing agent. Where this page compares one building or neighborhood to another, that is our analysis of the recorded record — it names the measure, the period and the sample it rests on, and it is an observation about medians rather than a prediction about any particular apartment.
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