12 S 1st St
12 S 1st St is a 13-story building in Downtown San Jose with 100% of its floor area within daylight reach of a facade. This screen estimates 99 homes and scores it 95 out of 100 for office-to-residential conversion suitability.
CA-18 · Screened 2026-10-20 · Strong candidate
Where 12 S 1st St is
Its block in Downtown San Jose, drawn from San Jose's own building outlines and street centerlines.
- Already housing
- Not screened
- 12 S 1st St
This building's conversion pencils at default assumptions without any subsidy.
This footprint has no windowless core at all: every point on the floor plate is within 35 ft of a facade, which is unusual and is the main reason it scores as well as it does.
Separated from its neighbors. The city’s map draws this building and the ones beside it as one outline with one height. This outline comes from OpenStreetMap, which maps them separately, and its height is OpenStreetMap’s.
Modeled conversion metrics for 12 S 1st St, 2026-10-20.
| Suitability scoreStrong candidate | 95 / 100 |
|---|---|
| Storiesfrom Business Wire, “Cushman & Wakefield Arranges $74.1 Million Financing for Bank of Italy Office-to-Residential Conversion”, in place of the 267 ft LiDAR height ÷ 12 ft floor-to-floor | 13 |
| Floor plateper floor, from the city footprint | 7,743 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 100% |
| Deepest interior pointviability threshold is 80 ft | 30 ft |
| Windowless coreper floor — renovated but never rentable | 0 sq ft |
| Estimated homesat 750 sq ft average | 99 |
| Conversion cost$405/sq ft all-in on 92,918 sq ft | $37.6M |
| Gap before grantpencils unsubsidized | -$4.4M |
| Modeled RESIDE grantbelow the statutory cap | $5.9M |
| BuiltSan Jose does not publish a construction year with this data | — |
| ZoningDowntown San Jose | DC |
| Opportunity Zonecensus tract 06085500901, 2018 designation | Yes |
The plan: window line, shape and floor rhythm
48 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 392 ft of exterior wall, and across 12 residential floors the building carries 4,707 ft of it in total, divided among the 99 homes this screen estimates.
Its plate is moderately compact at 0.63: 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 8.3 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 12 S 1st St scores 95 out of 100
Daylight efficiency 100, Interior depth 100, Scale 66, Finance 100 — each out of 100, then weighted.
Score components for 12 S 1st St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency100% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 100 | 45% | 45.0 |
| Interior depthdeepest interior point 30 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale99 estimated homes, scored from 0 up to 150 | 66 | 15% | 9.9 |
| Financecompleted value covers conversion cost with 28% to spare, which tops out the component | 100 | 15% | 15.0 |
Most of what it earns comes from daylight efficiency, and what holds it back most is scale, at 66 out of 100: 99 estimated homes, scored from 0 up to 150.
What the conversion would cost
$405 per square foot all-in across 92,918 sq ft of converted floor, or $37.6M in total — about $380K for each of the 99 homes.
All-in cost per square foot for 12 S 1st 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 circulation and service area that earns nothing directly. Against it the model sets a completed value of $425K a home, which for 99 homes is $42.1M.
What would have to be true
This one already clears the bar. The question is how much room it has before it stops.
At $425K a home, completed value covers the $37.6M of work with $4.4M to spare. Value per home would have to fall to $380K — 11% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $405 to $453 per square foot. Neither is a wide margin in a market that moves, but this building does not need a grant to work.
Each of these, moved on its own, would be enough to undo that for 12 S 1st St:
Single-assumption flip points for 12 S 1st St, each holding the other three at their defaults.
| Circulation efficiencythe binding constraint — the least this building would need | 21% downto 63% |
|---|---|
| Completed value per home | 25% downto $320K |
| Average unit size | 27% upto 953 sq ft |
| Conversion cost per square foot | 43% upto $372/sq ft |
All four are sliders in the survey, where 12 S 1st St re-scores against your own numbers.
How it compares in Downtown San Jose
12 S 1st St ranks 5th of the 47 buildings screened here, against a median score of 77.
Its floor plate is better lit than 100% of them, and shallower than 94% of them at its deepest interior point. On size it is the 35th largest by estimated homes. The full survey of all 47 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within the DC zone
5th of 40 zoned DC — the comparison that shares its rules, rents and streets.
40 of the screened buildings are zoned DC. 12 S 1st St ranks 5th of them against a median score of 78. 24 score 70 or more, their median deepest interior point is 59 ft from a facade against this building’s 30 ft, and together they would hold an estimated 8,653 homes. The group’s top scorer is 1 Almaden Blvd, at 100.
Its nearest match in size: 121 S Market St
The screened building closest to 12 S 1st St in converted floor area is 121 S Market St: 89,050 sq ft over 9 stories, against 92,918 sq ft over 13 here.
12 S 1st St scores 95 to its 84, and with the size held roughly equal most of that lead comes from interior depth: 100 out of 100 here, 69 there (deepest interior point 52 ft from a facade, scored from 80 ft down to 40 ft). On the money they part ways: 121 S Market St pencils only with the modeled RESIDE grant, while 12 S 1st St pencils without a subsidy. The two stand about 1,100 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 12 S 1st St $5.9M, 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 06085500901, 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 12 S 1st 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.
- 5 S 1st St10 stories · 100% daylit · 58 estimated homes · scores 91/100 (Strong candidate)about 160 ft away
- 75 E Santa Clara St14 stories · 79% daylit · 182 estimated homes · scores 78/100 (Strong candidate)about 450 ft away
- 84 W Santa Clara St8 stories · 92% daylit · 88 estimated homes · scores 93/100 (Strong candidate)about 460 ft away
- 52 E Santa Clara St6 stories · 60% daylit · 221 estimated homes · scores 35/100 (Marginal)about 470 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.