1500 Walnut St

Where 1500 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

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

The typical floor has 946 ft of exterior wall, and across 21 residential floors the building carries 19,875 ft of it in total, divided among the 537 homes this screen estimates.

Its plate is elongated at 0.37: a slab or an L, which is why so much of the floor lies within reach of a window: the outline buys daylight that a square plan of the same area would not. How window line and plate shape are measured.

At the model’s 750 sq ft average, the plan works out at about 25.6 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 1500 Walnut St scores 87 out of 100

Daylight efficiency 100, Interior depth 89, Scale 100, Finance 30 — each out of 100, then weighted.

Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 30 out of 100: remaining gap is 42% of conversion cost, scored from 60% down to 0%.

Built in 1928

Philadelphia records this building as going up in 1928, 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 91% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 556,113 sq ft of converted floor, or $200.2M in total — about $373K for each of the 537 homes.

That cost is charged across every converted square foot, including the 52,670 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 537 homes is $105.6M.

What would have to be true

A $94.6M gap before any grant, $84.6M after the modeled one. The smallest single change that would close it: average unit size 44% down.

The shortfall before any grant is $94.6M. Closing it from the value side means each of the 537 homes finishing at $373K rather than the $197K the model assumes — 90% more. Closing it from the cost side means getting all-in cost down from $360 to $190 per square foot.

A modeled RESIDE grant of $10.0M moves that threshold to $354K a home. That is still above the $197K assumed, leaving $84.6M uncovered, which is why the grant does not unlock this one.

Nor do all four levers have to move. For 1500 Walnut St, one alone would close the gap at:

All four are sliders in the survey, where 1500 Walnut St re-scores against your own numbers.

How it compares in Center City Philadelphia

1500 Walnut St ranks 16th of the 100 buildings screened here, against a median score of 67.

Its floor plate is better lit than 66% of them, and shallower than 70% of them at its deepest interior point. On size it is the 22nd 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

16th of 63 zoned CMX5 — the comparison that shares its rules, rents and streets.

63 of the screened buildings are zoned CMX5. 1500 Walnut St ranks 16th 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 44 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: 100 S Broad St

The screened building closest to 1500 Walnut St in converted floor area is 100 S Broad St: 592,747 sq ft over 22 stories, against 556,113 sq ft over 22 here.

The two land within a few points of each other — 87 here, 90 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 700 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 1500 Walnut St $10.0M, 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 1500 Walnut St

The 4 closest the screen also covers, from 230 ft away. They are the colored outlines on the plan at the top of this page.

• 1420 Walnut St
  15 stories · 95% daylit · 210 estimated homes · scores 92/100 (Strong candidate)
  about 230 ft away
• 1435 Walnut St
  6 stories · 99% daylit · 38 estimated homes · scores 82/100 (Strong candidate)
  about 280 ft away
• 1524 Walnut St
  21 stories · 86% daylit · 249 estimated homes · scores 81/100 (Strong candidate)
  about 300 ft away
• 1525 Locust St
  18 stories · 100% daylit · 121 estimated homes · scores 91/100 (Strong candidate)
  about 320 ft away