351 California St
351 California St is a 16-story building in Downtown San Francisco with 100% of its floor area within daylight reach of a facade. This screen estimates 162 homes and scores it 100 out of 100 for office-to-residential conversion suitability.
CA-11 · Screened 2026-10-12 · Strong candidate
No address point in San Francisco’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 351 California St is
Its block in Downtown San Francisco, drawn from San Francisco's own building outlines and street centerlines.
- Already housing
- Not screened
- 351 California St
This building does not pencil on its own, but a modeled RESIDE Act grant would close the gap if the building qualified for one.
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.
Modeled conversion metrics for 351 California St, 2026-10-12.
| Suitability scoreStrong candidate | 100 / 100 |
|---|---|
| Storiesfrom 217 ft LiDAR (2010) height ÷ 12 ft floor-to-floor | 16 |
| Floor plateper floor, from the city footprint | 10,161 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 100% |
| Deepest interior pointviability threshold is 80 ft | 29 ft |
| Windowless coreper floor — renovated but never rentable | 0 sq ft |
| Estimated homesat 750 sq ft average | 162 |
| Conversion cost$405/sq ft all-in on 152,416 sq ft | $61.7M |
| Gap before grantshortfall against completed value | $2.4M |
| Modeled RESIDE grantbelow the statutory cap | $9.7M |
| BuiltSan Francisco's own record of the construction year | 1920 |
| ZoningFinancial District/South Beach | C-3-O |
| Opportunity Zonenot in a 2018 designated tract | No |
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 560 ft of exterior wall, and across 15 residential floors the building carries 8,397 ft of it in total, divided among the 162 homes this screen estimates.
Its plate is elongated at 0.41: a slab or an L, which is why so much of the floor lies within reach of a window: the outline buys daylight that a square plan of the same area would not. How window line and plate shape are measured.
At the model’s 750 sq ft average, the plan works out at about 10.8 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 351 California St scores 100 out of 100
Daylight efficiency 100, Interior depth 100, Scale 100, Finance 100 — each out of 100, then weighted.
Score components for 351 California 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 29 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale162 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financecompleted value covers conversion cost with 12% to spare, which tops out the component | 100 | 15% | 15.0 |
Every component scores at or near full marks, so nothing in the geometry or the pro-forma is holding this one back — daylight efficiency carries the most weight of the four.
Built in 1920
San Francisco records this building as going up in 1920, which puts it in the interwar stock.
As a rule, steel or concrete frames with punched windows and plates still narrow enough for daylight to reach the middle, often with high ceilings. Among the most convertible stock there is, and the reason so many early conversions were of buildings this age. 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 100% daylight figure above deserves.
What the conversion would cost
$405 per square foot all-in across 152,416 sq ft of converted floor, or $61.7M in total — about $381K for each of the 162 homes.
All-in cost per square foot for 351 California 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 $366K a home, which for 162 homes is $59.3M.
What would have to be true
A $2.4M gap before any grant, which the modeled $9.7M closes. What would reopen it soonest: circulation efficiency 11% down.
The shortfall before any grant is $2.4M. Closing it from the value side means each of the 162 homes finishing at $381K rather than the $366K the model assumes — 4% more. Closing it from the cost side means getting all-in cost down from $405 to $389 per square foot.
A modeled RESIDE grant of $9.7M moves that threshold to $321K a home. That is below the assumed value, which is why this building counts as unlocked by the grant — subject to it qualifying under the law's vacant-and-abandoned test, which this data cannot show.
Each of these, moved on its own, would be enough to undo that for 351 California St:
Single-assumption flip points for 351 California St, each holding the other three at their defaults.
| Circulation efficiencythe binding constraint — the least this building would need | 11% downto 71% |
|---|---|
| Average unit size | 12% upto 841 sq ft |
| Completed value per home | 12% downto $321K |
| Conversion cost per square foot | 18% upto $308/sq ft |
All four are sliders in the survey, where 351 California St re-scores against your own numbers.
How it compares in Downtown San Francisco
351 California St ranks 1st of the 205 buildings screened here, against a median score of 87.
Its floor plate is better lit than 100% of them, and shallower than 85% of them at its deepest interior point. On size it is the 98th largest by estimated homes. The full survey of all 205 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within Financial District/South Beach and the C-3-O zone
1st of 165 in Financial District/South Beach, 1st of 88 zoned C-3-O — the comparison that shares its rules, rents and streets.
San Francisco places 165 of the screened buildings in Financial District/South Beach. 351 California St ranks 1st of them against a median score of 88, the top score in the group. 121 score 70 or more, their median deepest interior point is 47 ft from a facade against this building’s 29 ft, and together they would hold an estimated 40,456 homes. The group’s top scorer is 870 Market St, at 100.
88 of the screened buildings are zoned C-3-O. 351 California St ranks 1st of them against a median score of 89, the top score in the group. 76 score 70 or more, their median deepest interior point is 44 ft from a facade against this building’s 29 ft, and together they would hold an estimated 21,444 homes. The group’s top scorer is 266 Bush St, at 100.
Its nearest match in size: 160 Sansome St
The screened building closest to 351 California St in converted floor area is 160 Sansome St: 149,513 sq ft over 17 stories, against 152,416 sq ft over 16 here.
351 California St scores 100 to its 95, and with the size held roughly equal most of that lead comes from interior depth: 100 out of 100 here, 83 there (deepest interior point 47 ft from a facade, scored from 80 ft down to 40 ft). On the money they sit in the same place: each pencils only with the modeled RESIDE grant. The two stand about 400 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 351 California St $9.7M, 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 351 California St
The 4 closest the screen also covers, from 170 ft away. They are the colored outlines on the plan at the top of this page.
- 191 Battery St10 stories · 100% daylit · 77 estimated homes · scores 93/100 (Strong candidate)about 170 ft away
- 401 California St26 stories · 97% daylit · 181 estimated homes · scores 100/100 (Strong candidate)about 170 ft away
- 350 California St22 stories · 82% daylit · 303 estimated homes · scores 77/100 (Strong candidate)about 180 ft away
- 255 Battery St8 stories · 83% daylit · 88 estimated homes · scores 73/100 (Strong candidate)about 240 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.