461 N 3rd St
461 N 3rd St is a 5-story building in Center City Philadelphia with 100% of its floor area within daylight reach of a facade. This screen estimates 53 homes and scores it 84 out of 100 for office-to-residential conversion suitability.
PA-2 & PA-3 · Screened 2026-10-04 · Strong candidate
Where 461 N 3rd St is
Its block in Center City Philadelphia, drawn from Philadelphia's own building outlines and street centerlines.
- Already housing
- Not screened
- 461 N 3rd St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
This footprint has no windowless core at all: every point on the floor plate is within 35 ft of a facade, which is unusual and is the main reason it scores as well as it does.
Modeled conversion metrics for 461 N 3rd St, 2026-10-04.
| Suitability scoreStrong candidate | 84 / 100 |
|---|---|
| Storiesfrom 61 ft LiDAR height ÷ 12 ft floor-to-floor | 5 |
| Floor plateper floor, from the city footprint | 12,603 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 100% |
| Deepest interior pointviability threshold is 80 ft | 35 ft |
| Windowless coreper floor — renovated but never rentable | 0 sq ft |
| Estimated homesat 750 sq ft average | 53 |
| Conversion cost$360/sq ft all-in on 50,410 sq ft | $18.1M |
| Gap before grantshortfall against completed value | $7.7M |
| Modeled RESIDE grantbelow the statutory cap | $3.2M |
| BuiltPhiladelphia's own record of the construction year | 2002 |
| ZoningCenter City Philadelphia | CMX3 |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
44 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 582 ft of exterior wall, and across 4 residential floors the building carries 2,326 ft of it in total, divided among the 53 homes this screen estimates.
Its plate is moderately compact at 0.47: a squarish plan, with enough perimeter for a conventional double-loaded corridor. How window line and plate shape are measured.
At the model’s 750 sq ft average, the plan works out at about 13.3 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 461 N 3rd St scores 84 out of 100
Daylight efficiency 100, Interior depth 100, Scale 35, Finance 58 — each out of 100, then weighted.
Score components for 461 N 3rd St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency100% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 100 | 45% | 45.0 |
| Interior depthdeepest interior point 35 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale53 estimated homes, scored from 0 up to 150 | 35 | 15% | 5.3 |
| Financeremaining gap is 25% of conversion cost, scored from 60% down to 0% | 58 | 15% | 8.7 |
Most of what it earns comes from daylight efficiency, and what holds it back most is scale, at 35 out of 100: 53 estimated homes, scored from 0 up to 150.
Built in 2002
Philadelphia records this building as going up in 2002, which puts it in the modern stock.
As a rule, newer systems and better structure, but usually built deep and sealed for office use, and rarely cheap enough to buy at a price that lets a conversion pencil. That is the era’s general tendency rather than a finding about this building — the model reads an outline and a height, and can see nothing inside — but it is the first thing an architect would want to know, and it colours how much confidence the 100% daylight figure above deserves.
What the conversion would cost
$360 per square foot all-in across 50,410 sq ft of converted floor, or $18.1M in total — about $342K for each of the 53 homes.
All-in cost per square foot for 461 N 3rd St: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/sq ft |
|---|---|
| Plumbing risers to every unit | $40/sq ft |
| Operable windows and glazing | $30/sq ft |
| Additional egress stair | $18/sq ft |
| Fire sprinklers (NFPA 13R) | $12/sq ft |
| All-in | $360/sq ft |
That cost is charged across every converted square foot, including the circulation and service area that earns nothing directly. Against it the model sets a completed value of $197K a home, which for 53 homes is $10.4M.
What would have to be true
A $7.7M gap before any grant, $4.5M after the modeled one. The smallest single change that would close it: average unit size 24% down.
The shortfall before any grant is $7.7M. Closing it from the value side means each of the 53 homes finishing at $342K rather than the $197K the model assumes — 74% more. Closing it from the cost side means getting all-in cost down from $360 to $207 per square foot.
A modeled RESIDE grant of $3.2M moves that threshold to $282K a home. That is still above the $197K assumed, leaving $4.5M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 461 N 3rd St, one alone would close the gap at:
Single-assumption flip points for 461 N 3rd St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 24% downto 568 sq ft |
|---|---|
| Conversion cost per square foot | 35% downto $170/sq ft |
| Completed value per home | 44% upto $282K |
All four are sliders in the survey, where 461 N 3rd St re-scores against your own numbers.
How it compares in Center City Philadelphia
461 N 3rd St ranks 19th of the 100 buildings screened here, against a median score of 67.
Its floor plate is better lit than 100% of them, and shallower than 86% of them at its deepest interior point. On size it is the 78th largest by estimated homes. The full survey of all 100 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within the CMX3 zone
1st of 13 zoned CMX3 — the comparison that shares its rules, rents and streets.
13 of the screened buildings are zoned CMX3. 461 N 3rd St ranks 1st of them against a median score of 73, the top score in the group. 8 score 70 or more, their median deepest interior point is 51 ft from a facade against this building’s 35 ft, and together they would hold an estimated 1,053 homes.
Its nearest match in size: 2213 Chestnut St
The screened building closest to 461 N 3rd St in converted floor area is 2213 Chestnut St: 49,088 sq ft over 5 stories, against 50,410 sq ft over 5 here.
461 N 3rd St scores 84 to its 71, and with the size held roughly equal most of that lead comes from interior depth: 100 out of 100 here, 73 there (deepest interior point 51 ft from a facade, scored from 80 ft down to 40 ft). On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 9,800 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 461 N 3rd St $3.2M, on the assumption it qualifies. Whether it does, no published dataset can say.
That figure assumes the building meets the Act’s vacant-and-abandoned test, which turns on code-enforcement and receivership records no city publishes.
It does not sit in a 2018 designated Opportunity Zone, so it would not draw that Section 201 priority.
Other buildings screened near 461 N 3rd St
The 4 closest the screen also covers, from 520 ft away. They are the colored outlines on the plan at the top of this page.
- 309 Callowhill St6 stories · 76% daylit · 146 estimated homes · scores 62/100 (Worth a feasibility study)about 520 ft away
- 441 N 5th St4 stories · 73% daylit · 48 estimated homes · scores 46/100 (Marginal)about 880 ft away
- 520 N Christopher Columbus Blvd8 stories · 69% daylit · 131 estimated homes · scores 42/100 (Marginal)about 1,600 ft away
- 421 N 7th St7 stories · 85% daylit · 229 estimated homes · scores 79/100 (Strong candidate)about 1,770 ft away
A screen, not a feasibility study, from outlines and heights rather than plans: the method and how to correct a figure. If you know this building’s interior, you know what this model cannot see.