1500 Spring Garden St

Where 1500 Spring Garden 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

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

The typical floor has 1,834 ft of exterior wall, and across 11 residential floors the building carries 20,170 ft of it in total, divided among the 591 homes this screen estimates.

Its plate is moderately compact at 0.46: 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 53.7 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 1500 Spring Garden St scores 16 out of 100

Daylight efficiency 1, Interior depth 0, Scale 100, Finance 0 — each out of 100, then weighted.

Most of what it earns comes from scale, and what holds it back most is interior depth, at 0 out of 100: deepest interior point 146 ft from a facade, scored from 80 ft down to 40 ft.

Built in 1948

Philadelphia records this building as going up in 1948, which puts it in the post-war stock.

As a rule, the period when plates got deep and facades became curtain wall: sealed glazing, lower floor-to-floor heights, and mechanical systems designed around a sealed box. Conversions here usually turn on whether the windows can be made to open and whether ceilings survive new plumbing. 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 41% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 1,364,796 sq ft of converted floor, or $491.3M in total — about $831K for each of the 591 homes.

That cost is charged across every converted square foot, including the 810,708 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 591 homes is $116.2M.

What would have to be true

A $375.1M gap before any grant, $365.1M after the modeled one. The smallest single change that would close it: average unit size 76% down.

The shortfall before any grant is $375.1M. Closing it from the value side means each of the 591 homes finishing at $831K rather than the $197K the model assumes — 323% more. Closing it from the cost side means getting all-in cost down from $360 to $85 per square foot.

A modeled RESIDE grant of $10.0M moves that threshold to $814K a home. That is still above the $197K assumed, leaving $365.1M uncovered, which is why the grant does not unlock this one.

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

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

How it compares in Center City Philadelphia

1500 Spring Garden St ranks 102nd of the 103 buildings screened here, against a median score of 67.

Its floor plate is better lit than 2% of them, and shallower than 2% of them at its deepest interior point. On size it is the 19th largest by estimated homes. The full survey of all 103 buildings ranks and maps every one of them, and the list by address links each to its own page.

Within the CMX4 zone

15th of 15 zoned CMX4 — the comparison that shares its rules, rents and streets.

15 of the screened buildings are zoned CMX4. 1500 Spring Garden St ranks 15th of them against a median score of 58. 5 score 70 or more, their median deepest interior point is 64 ft from a facade against this building’s 146 ft, and together they would hold an estimated 4,016 homes. The group’s top scorer is 901 Arch St, at 84.

Its nearest match in size: 508 Walnut St

The screened building closest to 1500 Spring Garden St in converted floor area is 508 Walnut St: 1,379,079 sq ft over 20 stories, against 1,364,796 sq ft over 12 here.

1500 Spring Garden St scores 16 to its 23, and with the size held roughly equal most of that shortfall comes from daylight efficiency: 1 out of 100 here, 17 there (48% of the floor area within 35 ft of a facade, scored from 40% up to 90%). On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 6,600 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 1500 Spring Garden 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 Spring Garden St

The 4 closest the screen also covers, from 1,420 ft away. They are the colored outlines on the plan at the top of this page.

• 642 N Broad St
  6 stories · 69% daylit · 187 estimated homes · scores 35/100 (Marginal)
  about 1,420 ft away
• 211 N 13th St
  9 stories · 92% daylit · 78 estimated homes · scores 81/100 (Strong candidate)
  about 2,320 ft away
• 1025 Callowhill St
  5 stories · 88% daylit · 50 estimated homes · scores 73/100 (Strong candidate)
  about 2,460 ft away
• 319 N 11th St
  6 stories · 95% daylit · 44 estimated homes · scores 82/100 (Strong candidate)
  about 2,500 ft away