181 E Santa Clara St
181 E Santa Clara St is a 25-story building in Downtown San Jose with 57% of its floor area within daylight reach of a facade. This screen estimates 819 homes and scores it 35 out of 100 for office-to-residential conversion suitability.
CA-18 · Screened 2026-09-12 · Marginal
Also addressed as 28 N 4th St: San Jose’s address records place both on this one footprint.
Where 181 E Santa Clara St is
Its block in Downtown San Jose, drawn from San Jose's own building outlines and street centerlines.
- Already housing
- Not screened
- 181 E Santa Clara St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Every floor carries 24,367 sq ft of windowless core — area that must be gutted, seismically braced and sprinklered but can never be rented as an apartment. Across 24 residential floors that is 584,803 sq ft of cost carrying no revenue.
Modeled conversion metrics for 181 E Santa Clara St, 2026-09-12.
| Suitability scoreMarginal | 35 / 100 |
|---|---|
| Storiesfrom 300 ft LiDAR height ÷ 12 ft floor-to-floor | 25 |
| Floor plateper floor, from the city footprint | 56,365 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 57% |
| Deepest interior pointviability threshold is 80 ft | 93 ft |
| Windowless coreper floor — renovated but never rentable | 24,367 sq ft |
| Estimated homesat 750 sq ft average | 819 |
| Conversion cost$405/sq ft all-in on 1,352,772 sq ft | $547.9M |
| Gap before grantshortfall against completed value | $199.8M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltSan Jose does not publish a construction year with this data | — |
| ZoningDowntown San Jose | DC |
| Opportunity Zonecensus tract 06085501000, 2018 designation | Yes |
The plan: window line, shape and floor rhythm
36 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 1,217 ft of exterior wall, and across 24 residential floors the building carries 29,205 ft of it in total, divided among the 819 homes this screen estimates.
Its plate is moderately compact at 0.48: 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 34.1 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 181 E Santa Clara St scores 35 out of 100
The weighted components add to 36, 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.
Score components for 181 E Santa Clara St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency57% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 34 | 45% | 15.1 |
| Interior depthdeepest interior point 93 ft from a facade, scored from 80 ft down to 40 ft | 0 | 25% | 0.0 |
| Scale819 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 35% of conversion cost, scored from 60% down to 0% | 42 | 15% | 6.3 |
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.
What the conversion would cost
$405 per square foot all-in across 1,352,772 sq ft of converted floor, or $547.9M in total — about $669K for each of the 819 homes.
All-in cost per square foot for 181 E Santa Clara St: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/sq ft |
|---|---|
| Seismic retrofit (change of use) | $45/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 | $405/sq ft |
That cost is charged across every converted square foot, including the 584,803 sq ft of windowless core, which has to be gutted, seismically braced and sprinklered like the rest of the building and then earns nothing. Against it the model sets a completed value of $425K a home, which for 819 homes is $348.1M.
What would have to be true
A $199.8M gap before any grant, $189.8M after the modeled one. The smallest single change that would close it: average unit size 35% down.
The shortfall before any grant is $199.8M. Closing it from the value side means each of the 819 homes finishing at $669K rather than the $425K the model assumes — 57% more. Closing it from the cost side means getting all-in cost down from $405 to $257 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $657K a home. That is still above the $425K assumed, leaving $189.8M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 181 E Santa Clara St, one alone would close the gap at:
Single-assumption flip points for 181 E Santa Clara St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 35% downto 485 sq ft |
|---|---|
| Conversion cost per square foot | 54% downto $120/sq ft |
| Completed value per home | 55% upto $657K |
All four are sliders in the survey, where 181 E Santa Clara St re-scores against your own numbers.
How it compares in Downtown San Jose
181 E Santa Clara St ranks 59th of the 82 buildings screened here, against a median score of 64.
Its floor plate is better lit than 21% of them, and shallower than 23% of them at its deepest interior point. On size it is the 5th largest by estimated homes. The full survey of all 82 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within the DC zone
50th of 72 zoned DC — the comparison that shares its rules, rents and streets.
72 of the screened buildings are zoned DC. 181 E Santa Clara St ranks 50th of them against a median score of 61. 31 score 70 or more, their median deepest interior point is 68 ft from a facade against this building’s 93 ft, and together they would hold an estimated 23,276 homes. The group’s top scorer is 1 Almaden Blvd, at 100.
Its nearest match in size: 220 Almaden Blvd
The screened building closest to 181 E Santa Clara St in converted floor area is 220 Almaden Blvd: 1,466,926 sq ft over 25 stories, against 1,352,772 sq ft over 25 here.
181 E Santa Clara St scores 35 to its 28, and with the size held roughly equal most of that lead comes from daylight efficiency: 34 out of 100 here, 19 there (50% 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 3,000 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 181 E Santa Clara 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 06085501000, 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 181 E Santa Clara St
The 4 closest the screen also covers, from 210 ft away. They are the colored outlines on the plan at the top of this page.
- 50 N 4th St7 stories · 56% daylit · 178 estimated homes · scores 35/100 (Marginal)about 210 ft away
- 26 N 5th St7 stories · 80% daylit · already an apartment buildingabout 320 ft away
- 225 E Santa Clara St (south)13 stories · 87% daylit · 257 estimated homes · scores 90/100 (Strong candidate)about 360 ft away
- 156 E St John St7 stories · 83% daylit · already an apartment buildingabout 360 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.