642 N Broad St

Where 642 N Broad 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 1,373 ft of exterior wall, and across 5 residential floors the building carries 6,866 ft of it in total, divided among the 187 homes this screen estimates.

Its plate is elongated at 0.34: 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 37.4 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 642 N Broad St scores 35 out of 100

The weighted components add to 44, but the score is capped at 35 because its deepest interior point is 93 ft from a facade, past the 80 ft threshold beyond which conversion requires carving a light well.

Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 0 out of 100: deepest interior point 93 ft from a facade, scored from 80 ft down to 40 ft.

Built in 1903

Philadelphia records this building as going up in 1903, which puts it in the pre-1920 stock.

As a rule, the era that converts most readily: load-bearing masonry, small floor plates laid out before deep-plan offices were possible, operable windows and generous floor-to-floor heights. The usual obstacles are not daylight but hazardous materials, lifts and bringing structure up to current code. 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 69% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 254,191 sq ft of converted floor, or $91.5M in total — about $489K for each of the 187 homes.

That cost is charged across every converted square foot, including the 78,182 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 187 homes is $36.8M.

What would have to be true

A $54.7M gap before any grant, $44.7M after the modeled one. The smallest single change that would close it: average unit size 55% down.

The shortfall before any grant is $54.7M. Closing it from the value side means each of the 187 homes finishing at $489K rather than the $197K the model assumes — 149% more. Closing it from the cost side means getting all-in cost down from $360 to $145 per square foot.

A modeled RESIDE grant of $10.0M moves that threshold to $436K a home. That is still above the $197K assumed, leaving $44.7M uncovered, which is why the grant does not unlock this one.

Nor do all four levers have to move. For 642 N Broad St, one alone would close the gap at:

All four are sliders in the survey, where 642 N Broad St re-scores against your own numbers.

How it compares in Center City Philadelphia

642 N Broad St ranks 82nd of the 103 buildings screened here, against a median score of 67.

Its floor plate is better lit than 35% of them, and shallower than 9% of them at its deepest interior point. On size it is the 55th 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.

Its nearest match in size: 421 N 7th St

The screened building closest to 642 N Broad St in converted floor area is 421 N 7th St: 252,495 sq ft over 7 stories, against 254,191 sq ft over 6 here.

421 N 7th St scores 79 and 642 N Broad St only 35, and the difference is a hard fail rather than a matter of degree: the lower one is capped at 35 because its deepest interior point is 93 ft from a facade, past the 80 ft threshold beyond which conversion requires carving a light well. On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 4,000 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 642 N Broad 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.

This building does sit in census tract 42101013300, a 2018 designated Opportunity Zone, which Section 201 lets HUD favor — one of the few statutory priorities this screen can actually check.

Other buildings screened near 642 N Broad 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.

• 1500 Spring Garden St
  12 stories · 41% daylit · 591 estimated homes · scores 16/100 (Unlikely)
  about 1,420 ft away
• 990 Spring Garden St
  7 stories · 76% daylit · 109 estimated homes · scores 63/100 (Worth a feasibility study)
  about 2,550 ft away
• 448 N 10th St
  7 stories · 100% daylit · 52 estimated homes · scores 84/100 (Strong candidate)
  about 2,580 ft away
• 1025 Callowhill St
  5 stories · 88% daylit · 50 estimated homes · scores 73/100 (Strong candidate)
  about 2,780 ft away