464 California St
464 California St is a 12-story building in Downtown San Francisco with 82% of its floor area within daylight reach of a facade. This screen estimates 299 homes and scores it 82 out of 100 for office-to-residential conversion suitability.
CA-11 · Screened 2026-10-12 · Strong candidate
Also addressed as 420 Montgomery St: San Francisco’s address records place both on this one footprint.
Where 464 California St is
Its block in Downtown San Francisco, drawn from San Francisco's own building outlines and street centerlines.
- Already housing
- Not screened
- 464 California St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Every floor carries 5,543 sq ft of windowless core — area that must be gutted, seismically braced and sprinklered but can never be rented as an apartment. Across 11 residential floors that is 60,970 sq ft of cost carrying no revenue.
Modeled conversion metrics for 464 California St, 2026-10-12.
| Suitability scoreStrong candidate | 82 / 100 |
|---|---|
| Storiesfrom 194 ft LiDAR (2010) height ÷ 12 ft floor-to-floor | 12 |
| Floor plateper floor, from the city footprint | 31,095 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 82% |
| Deepest interior pointviability threshold is 80 ft | 52 ft |
| Windowless coreper floor — renovated but never rentable | 5,543 sq ft |
| Estimated homesat 750 sq ft average | 299 |
| Conversion cost$405/sq ft all-in on 342,046 sq ft | $138.5M |
| Gap before grantshortfall against completed value | $29.1M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltSan Francisco's own record of the construction year | 1959 |
| ZoningFinancial District/South Beach | C-3-O |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
37 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 1,003 ft of exterior wall, and across 11 residential floors the building carries 11,031 ft of it in total, divided among the 299 homes this screen estimates.
Its plate is elongated at 0.39: 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 27.2 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 464 California St scores 82 out of 100
Daylight efficiency 84, Interior depth 70, Scale 100, Finance 77 — each out of 100, then weighted.
Score components for 464 California St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency82% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 84 | 45% | 38.0 |
| Interior depthdeepest interior point 52 ft from a facade, scored from 80 ft down to 40 ft | 70 | 25% | 17.4 |
| Scale299 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 14% of conversion cost, scored from 60% down to 0% | 77 | 15% | 11.6 |
Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 70 out of 100: deepest interior point 52 ft from a facade, scored from 80 ft down to 40 ft.
Built in 1959
San Francisco records this building as going up in 1959, which puts it in the post-war stock.
As a rule, the period when plates got deep and facades became curtain wall: sealed glazing, lower floor-to-floor heights, and mechanical systems designed around a sealed box. Conversions here usually turn on whether the windows can be made to open and whether ceilings survive new plumbing. 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 82% daylight figure above deserves.
What the conversion would cost
$405 per square foot all-in across 342,046 sq ft of converted floor, or $138.5M in total — about $463K for each of the 299 homes.
All-in cost per square foot for 464 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 60,970 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 $366K a home, which for 299 homes is $109.4M.
What would have to be true
A $29.1M gap before any grant, $19.1M after the modeled one. The smallest single change that would close it: average unit size 15% down.
The shortfall before any grant is $29.1M. Closing it from the value side means each of the 299 homes finishing at $463K rather than the $366K the model assumes — 27% more. Closing it from the cost side means getting all-in cost down from $405 to $320 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $430K a home. That is still above the $366K assumed, leaving $19.1M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 464 California St, one alone would close the gap at:
Single-assumption flip points for 464 California St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 15% downto 639 sq ft |
|---|---|
| Circulation efficiency | 17% upto 94% |
| Completed value per home | 17% upto $430K |
| Conversion cost per square foot | 21% downto $204/sq ft |
All four are sliders in the survey, where 464 California St re-scores against your own numbers.
How it compares in Downtown San Francisco
464 California St ranks 122nd of the 205 buildings screened here, against a median score of 87.
Its floor plate is better lit than 37% of them, and shallower than 44% of them at its deepest interior point. On size it is the 54th 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
101st of 165 in Financial District/South Beach, 63rd 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. 464 California St ranks 101st of them against a median score of 88. 121 score 70 or more, their median deepest interior point is 47 ft from a facade against this building’s 52 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. 464 California St ranks 63rd of them against a median score of 89. 76 score 70 or more, their median deepest interior point is 44 ft from a facade against this building’s 52 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: 537 Sacramento St
The screened building closest to 464 California St in converted floor area is 537 Sacramento St: 351,525 sq ft over 15 stories, against 342,046 sq ft over 12 here.
464 California St scores 82 to its 64, and with the size held roughly equal most of that lead comes from daylight efficiency: 84 out of 100 here, 65 there (73% 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 200 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 464 California 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.
It does not sit in a 2018 designated Opportunity Zone, so it would not draw that Section 201 priority.
Other buildings screened near 464 California St
The 4 closest the screen also covers, from 110 ft away. They are the colored outlines on the plan at the top of this page.
- 456 Montgomery St26 stories · 93% daylit · 259 estimated homes · scores 96/100 (Strong candidate)about 110 ft away
- 400 Montgomery St11 stories · 100% daylit · 109 estimated homes · scores 96/100 (Strong candidate)about 120 ft away
- 430 California St21 stories · 88% daylit · 215 estimated homes · scores 91/100 (Strong candidate)about 160 ft away
- 537 Sacramento St15 stories · 73% daylit · 272 estimated homes · scores 64/100 (Worth a feasibility study)about 200 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.