1742 South St
1742 South St is a 5-story building in Center City Philadelphia with 98% of its floor area within daylight reach of a facade. This screen estimates 40 homes and scores it 82 out of 100 for office-to-residential conversion suitability.
PA-2 & PA-3 · Screened 2026-09-15 · Strong candidate
No address point in Philadelphia’s records falls inside this footprint, so it is named by the closest one that no other screened building claims — usually a site entrance, but check the outline on the plan below before relying on the street number.
Where 1742 South St is
Its block in Center City Philadelphia, drawn from Philadelphia's own building outlines and street centerlines.
- Already housing
- Not screened
- 1742 South St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Every floor carries 235 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment. Across 4 residential floors that is 941 sq ft of cost carrying no revenue.
Modeled conversion metrics for 1742 South St, 2026-09-15.
| Suitability scoreStrong candidate | 82 / 100 |
|---|---|
| Storiesfrom 83 ft LiDAR height ÷ 12 ft floor-to-floor | 5 |
| Floor plateper floor, from the city footprint | 9,760 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 98% |
| Deepest interior pointviability threshold is 80 ft | 38 ft |
| Windowless coreper floor — renovated but never rentable | 235 sq ft |
| Estimated homesat 750 sq ft average | 40 |
| Conversion cost$360/sq ft all-in on 39,041 sq ft | $14.1M |
| Gap before grantshortfall against completed value | $6.2M |
| Modeled RESIDE grantbelow the statutory cap | $2.4M |
| BuiltPhiladelphia's own record of the construction year | 1986 |
| ZoningCenter City Philadelphia | CMX2 |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
44 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 444 ft of exterior wall, and across 4 residential floors the building carries 1,777 ft of it in total, divided among the 40 homes this screen estimates.
Its plate is moderately compact at 0.62: 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 10.0 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 1742 South St scores 82 out of 100
Daylight efficiency 100, Interior depth 100, Scale 27, Finance 55 — each out of 100, then weighted.
Score components for 1742 South St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency98% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 100 | 45% | 45.0 |
| Interior depthdeepest interior point 38 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale40 estimated homes, scored from 0 up to 150 | 27 | 15% | 4.0 |
| Financeremaining gap is 27% of conversion cost, scored from 60% down to 0% | 55 | 15% | 8.3 |
Most of what it earns comes from daylight efficiency, and what holds it back most is scale, at 27 out of 100: 40 estimated homes, scored from 0 up to 150.
Built in 1986
Philadelphia records this building as going up in 1986, 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 98% daylight figure above deserves.
What the conversion would cost
$360 per square foot all-in across 39,041 sq ft of converted floor, or $14.1M in total — about $351K for each of the 40 homes.
All-in cost per square foot for 1742 South St: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/sq ft |
|---|---|
| Plumbing risers to every unit | $40/sq ft |
| Operable windows and glazing | $30/sq ft |
| Additional egress stair | $18/sq ft |
| Fire sprinklers (NFPA 13R) | $12/sq ft |
| All-in | $360/sq ft |
That cost is charged across every converted square foot, including the 941 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 40 homes is $7.9M.
What would have to be true
A $6.2M gap before any grant, $3.8M after the modeled one. The smallest single change that would close it: average unit size 26% down.
The shortfall before any grant is $6.2M. Closing it from the value side means each of the 40 homes finishing at $351K rather than the $197K the model assumes — 79% more. Closing it from the cost side means getting all-in cost down from $360 to $202 per square foot.
A modeled RESIDE grant of $2.4M moves that threshold to $291K a home. That is still above the $197K assumed, leaving $3.8M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 1742 South St, one alone would close the gap at:
Single-assumption flip points for 1742 South St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 26% downto 554 sq ft |
|---|---|
| Conversion cost per square foot | 37% downto $163/sq ft |
| Completed value per home | 48% upto $291K |
All four are sliders in the survey, where 1742 South St re-scores against your own numbers.
How it compares in Center City Philadelphia
1742 South St ranks 27th of the 103 buildings screened here, against a median score of 67.
Its floor plate is better lit than 80% of them, and shallower than 83% of them at its deepest interior point. On size it is the 93rd 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: 232 Market St
The screened building closest to 1742 South St in converted floor area is 232 Market St: 37,164 sq ft over 5 stories, against 39,041 sq ft over 5 here.
The two land within a few points of each other — 82 here, 83 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 7,700 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 1742 South St $2.4M, 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 1742 South St
The 4 closest the screen also covers, from 2,050 ft away. They are the colored outlines on the plan at the top of this page.
- 1525 Locust St18 stories · 100% daylit · 121 estimated homes · scores 91/100 (Strong candidate)about 2,050 ft away
- 1524 Walnut St21 stories · 86% daylit · 249 estimated homes · scores 81/100 (Strong candidate)about 2,280 ft away
- 1619 Walnut St6 stories · 100% daylit · 33 estimated homes · scores 82/100 (Strong candidate)about 2,340 ft away
- 1500 Walnut St22 stories · 91% daylit · 537 estimated homes · scores 87/100 (Strong candidate)about 2,350 ft away
A screen, not a feasibility study, from outlines and heights rather than plans: the method and how to correct a figure. If you know this building’s interior, you know what this model cannot see.