1801 Market St

Where 1801 Market 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 684 ft of exterior wall, and across 26 residential floors the building carries 17,778 ft of it in total, divided among the 527 homes this screen estimates.

Its plate is compact at 0.78: 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 20.3 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 1801 Market St scores 40 out of 100

Daylight efficiency 51, Interior depth 5, Scale 100, Finance 3 — each out of 100, then weighted.

Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 3 out of 100: remaining gap is 58% of conversion cost, scored from 60% down to 0%.

Built in 1982

Philadelphia records this building as going up in 1982, which puts it in the late-modern stock.

As a rule, typically the hardest to convert: the deepest plates of any era, large central cores, and floor-to-floor heights tight enough that running residential drainage under a ceiling can be the thing that ends a project. 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 66% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 754,333 sq ft of converted floor, or $271.6M in total — about $515K for each of the 527 homes.

That cost is charged across every converted square foot, including the 259,518 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 527 homes is $103.7M.

What would have to be true

A $167.9M gap before any grant, $157.9M after the modeled one. The smallest single change that would close it: average unit size 60% down.

The shortfall before any grant is $167.9M. Closing it from the value side means each of the 527 homes finishing at $515K rather than the $197K the model assumes — 162% more. Closing it from the cost side means getting all-in cost down from $360 to $137 per square foot.

A modeled RESIDE grant of $10.0M moves that threshold to $496K a home. That is still above the $197K assumed, leaving $157.9M uncovered, which is why the grant does not unlock this one.

Nor do all four levers have to move. For 1801 Market St, one alone would close the gap at:

All four are sliders in the survey, where 1801 Market St re-scores against your own numbers.

How it compares in Center City Philadelphia

1801 Market St ranks 76th of the 103 buildings screened here, against a median score of 67.

Its floor plate is better lit than 26% of them, and shallower than 23% of them at its deepest interior point. On size it is the 23rd 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 CMX5 zone

44th of 65 zoned CMX5 — the comparison that shares its rules, rents and streets.

65 of the screened buildings are zoned CMX5. 1801 Market St ranks 44th of them against a median score of 67. 28 score 70 or more, their median deepest interior point is 58 ft from a facade against this building’s 78 ft, and together they would hold an estimated 30,650 homes. The group’s top scorer is 112 N Broad St, at 93.

Its nearest match in size: 1622 Arch St

The screened building closest to 1801 Market St in converted floor area is 1622 Arch St: 712,335 sq ft over 27 stories, against 754,333 sq ft over 27 here.

1801 Market St scores 40 and 1622 Arch 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 80 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 900 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 1801 Market 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 1801 Market St

The 4 closest the screen also covers, from 160 ft away. They are the colored outlines on the plan at the top of this page.

• 1800 John F Kennedy Blvd
  20 stories · 98% daylit · 278 estimated homes · scores 92/100 (Strong candidate)
  about 160 ft away
• 1835 Market St
  29 stories · 63% daylit · 565 estimated homes · scores 36/100 (Marginal)
  about 210 ft away
• 1880 John F Kennedy Blvd
  20 stories · 99% daylit · 272 estimated homes · scores 92/100 (Strong candidate)
  about 250 ft away
• 1818 Market St
  40 stories · 62% daylit · 852 estimated homes · scores 35/100 (Marginal)
  about 300 ft away