1601 Walnut St

Where 1601 Walnut St is

Its block in Center City Philadelphia, drawn from Philadelphia's own building outlines and street centerlines.

The plan: window line, shape and floor rhythm

41 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.

The typical floor has 409 ft of exterior wall, and across 14 residential floors the building carries 5,733 ft of it in total, divided among the 140 homes this screen estimates.

Its plate is compact at 0.74: close to a square or a circle, the most efficient envelope an office can have and the least generous one for apartments: little perimeter to divide among homes. How window line and plate shape are measured.

At the model’s 750 sq ft average, the plan works out at about 10.0 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 1601 Walnut St scores 92 out of 100

Daylight efficiency 100, Interior depth 100, Scale 93, Finance 54 — each out of 100, then weighted.

Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 54 out of 100: remaining gap is 28% of conversion cost, scored from 60% down to 0%.

Built in 1925

Philadelphia records this building as going up in 1925, which puts it in the interwar stock.

As a rule, steel or concrete frames with punched windows and plates still narrow enough for daylight to reach the middle, often with high ceilings. Among the most convertible stock there is, and the reason so many early conversions were of buildings this age. 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 95% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 138,332 sq ft of converted floor, or $49.8M in total — about $356K for each of the 140 homes.

That cost is charged across every converted square foot, including the 6,272 sq ft of windowless core, which has to be gutted, re-plumbed and sprinklered like the rest of the building and then earns nothing. Against it the model sets a completed value of $197K a home, which for 140 homes is $27.5M.

What would have to be true

A $22.3M gap before any grant, $13.9M after the modeled one. The smallest single change that would close it: average unit size 31% down.

The shortfall before any grant is $22.3M. Closing it from the value side means each of the 140 homes finishing at $356K rather than the $197K the model assumes — 81% more. Closing it from the cost side means getting all-in cost down from $360 to $199 per square foot.

A modeled RESIDE grant of $8.4M moves that threshold to $296K a home. That is still above the $197K assumed, leaving $13.9M uncovered, which is why the grant does not unlock this one.

Nor do all four levers have to move. For 1601 Walnut St, one alone would close the gap at:

All four are sliders in the survey, where 1601 Walnut St re-scores against your own numbers.

How it compares in Center City Philadelphia

1601 Walnut St ranks 7th of the 100 buildings screened here, against a median score of 67.

Its floor plate is better lit than 75% of them, and shallower than 77% of them at its deepest interior point. On size it is the 59th 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 CMX5 zone

7th of 63 zoned CMX5 — the comparison that shares its rules, rents and streets.

63 of the screened buildings are zoned CMX5. 1601 Walnut St ranks 7th of them against a median score of 67. 28 score 70 or more, their median deepest interior point is 57 ft from a facade against this building’s 39 ft, and together they would hold an estimated 30,185 homes. The group’s top scorer is 112 N Broad St, at 93.

Its nearest match in size: 112 N Broad St

The screened building closest to 1601 Walnut St in converted floor area is 112 N Broad St: 135,931 sq ft over 13 stories, against 138,332 sq ft over 15 here.

The two land within a few points of each other — 92 here, 93 there — so at this size the screen reads them as much the same prospect. On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 2,100 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 1601 Walnut St $8.4M, 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 1601 Walnut St

The 4 closest the screen also covers, from 200 ft away. They are the colored outlines on the plan at the top of this page.

• 1619 Walnut St
  6 stories · 100% daylit · 33 estimated homes · scores 82/100 (Strong candidate)
  about 200 ft away
• 1524 Walnut St
  21 stories · 86% daylit · 249 estimated homes · scores 81/100 (Strong candidate)
  about 230 ft away
• 1524 Chestnut St
  4 stories · 100% daylit · 32 estimated homes · scores 82/100 (Strong candidate)
  about 390 ft away
• 1525 Locust St
  18 stories · 100% daylit · 121 estimated homes · scores 91/100 (Strong candidate)
  about 470 ft away