5 S 1st St
5 S 1st St is a 10-story building in Downtown San Jose with 100% of its floor area within daylight reach of a facade. This screen estimates 58 homes and scores it 91 out of 100 for office-to-residential conversion suitability.
CA-18 · Screened 2026-10-20 · Strong candidate
Also addressed as 2 W Santa Clara St: San Jose’s address records place both on this one footprint.
Where 5 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
- 5 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 floor count is OpenStreetMap’s.
Modeled conversion metrics for 5 S 1st St, 2026-10-20.
| Suitability scoreStrong candidate | 91 / 100 |
|---|---|
| Storiesfrom OpenStreetMap, “2 West Santa Clara, way 435423226”, in place of the 120 ft LiDAR height ÷ 12 ft floor-to-floor | 10 |
| Floor plateper floor, from the city footprint | 6,086 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 100% |
| Deepest interior pointviability threshold is 80 ft | 28 ft |
| Windowless coreper floor — renovated but never rentable | 0 sq ft |
| Estimated homesat 750 sq ft average | 58 |
| Conversion cost$405/sq ft all-in on 54,771 sq ft | $22.2M |
| Gap before grantpencils unsubsidized | -$2.5M |
| Modeled RESIDE grantbelow the statutory cap | $3.5M |
| BuiltSan Jose does not publish a construction year with this data | — |
| ZoningDowntown San Jose | DC |
| Opportunity Zonecensus tract 06085500800, 2018 designation | Yes |
The plan: window line, shape and floor rhythm
52 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 338 ft of exterior wall, and across 9 residential floors the building carries 3,044 ft of it in total, divided among the 58 homes this screen estimates.
Its plate is moderately compact at 0.67: 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 6.4 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 5 S 1st St scores 91 out of 100
Daylight efficiency 100, Interior depth 100, Scale 39, Finance 100 — each out of 100, then weighted.
Score components for 5 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 28 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale58 estimated homes, scored from 0 up to 150 | 39 | 15% | 5.8 |
| Financecompleted value covers conversion cost with 27% 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 39 out of 100: 58 estimated homes, scored from 0 up to 150.
What the conversion would cost
$405 per square foot all-in across 54,771 sq ft of converted floor, or $22.2M in total — about $382K for each of the 58 homes.
All-in cost per square foot for 5 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 58 homes is $24.6M.
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 $22.2M of work with $2.5M to spare. Value per home would have to fall to $382K — 10% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $405 to $450 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 5 S 1st St:
Single-assumption flip points for 5 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 | 24% downto $322K |
| Average unit size | 27% upto 953 sq ft |
| Conversion cost per square foot | 42% upto $369/sq ft |
All four are sliders in the survey, where 5 S 1st St re-scores against your own numbers.
How it compares in Downtown San Jose
5 S 1st St ranks 8th 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 100% of them at its deepest interior point. On size it is the 40th 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
8th of 40 zoned DC — the comparison that shares its rules, rents and streets.
40 of the screened buildings are zoned DC. 5 S 1st St ranks 8th 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 28 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: 255 W Julian St
The screened building closest to 5 S 1st St in converted floor area is 255 W Julian St: 58,140 sq ft over 6 stories, against 54,771 sq ft over 10 here.
The two land within a few points of each other — 91 here, 89 there — so at this size the screen reads them as much the same prospect. On the money they sit in the same place: each pencils without a subsidy. The two stand about 1,900 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 5 S 1st St $3.5M, 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 06085500800, 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 5 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.
- 12 S 1st St13 stories · 100% daylit · 99 estimated homes · scores 95/100 (Strong candidate)about 160 ft away
- 84 W Santa Clara St8 stories · 92% daylit · 88 estimated homes · scores 93/100 (Strong candidate)about 310 ft away
- 81 Post St7 stories · 100% daylit · 38 estimated homes · scores 89/100 (Strong candidate)about 390 ft away
- 60 S Market St15 stories · 79% daylit · 198 estimated homes · scores 78/100 (Strong candidate)about 490 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.