40 Leavenworth St
40 Leavenworth St is a 6-story building in Downtown San Francisco with 100% of its floor area within daylight reach of a facade. This screen estimates 68 homes and scores it 92 out of 100 for office-to-residential conversion suitability.
CA-11 · Screened 2026-10-12 · Strong candidate
Also addressed as 1128 Market St and 10 United Nations Plz: San Francisco’s address records place all 3 on this one footprint.
Where 40 Leavenworth St is
Its block in Downtown San Francisco, drawn from San Francisco's own building outlines and street centerlines.
- Already housing
- Not screened
- 40 Leavenworth 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 40 Leavenworth St, 2026-10-12.
| Suitability scoreStrong candidate | 92 / 100 |
|---|---|
| Storiesfrom 81 ft LiDAR (2010) height ÷ 12 ft floor-to-floor | 6 |
| Floor plateper floor, from the city footprint | 12,785 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 100% |
| Deepest interior pointviability threshold is 80 ft | 34 ft |
| Windowless coreper floor — renovated but never rentable | 0 sq ft |
| Estimated homesat 750 sq ft average | 68 |
| Conversion cost$405/sq ft all-in on 63,924 sq ft | $25.9M |
| Gap before grantshortfall against completed value | $1.0M |
| Modeled RESIDE grantbelow the statutory cap | $4.1M |
| BuiltSan Francisco's own record of the construction year | 1982 |
| ZoningTenderloin | C-3-G |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
44 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 596 ft of exterior wall, and across 5 residential floors the building carries 2,981 ft of it in total, divided among the 68 homes this screen estimates.
Its plate is moderately compact at 0.45: 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 13.6 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 40 Leavenworth St scores 92 out of 100
Daylight efficiency 100, Interior depth 100, Scale 45, Finance 100 — each out of 100, then weighted.
Score components for 40 Leavenworth 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 34 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale68 estimated homes, scored from 0 up to 150 | 45 | 15% | 6.8 |
| Financecompleted value covers conversion cost with 12% 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 45 out of 100: 68 estimated homes, scored from 0 up to 150.
Built in 1982
San Francisco records this building as going up in 1982, which puts it in the late-modern stock.
As a rule, typically the hardest to convert: the deepest plates of any era, large central cores, and floor-to-floor heights tight enough that running residential drainage under a ceiling can be the thing that ends a project. 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 63,924 sq ft of converted floor, or $25.9M in total — about $381K for each of the 68 homes.
All-in cost per square foot for 40 Leavenworth 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 68 homes is $24.9M.
What would have to be true
A $1.0M gap before any grant, which the modeled $4.1M closes. What would reopen it soonest: circulation efficiency 11% down.
The shortfall before any grant is $1.0M. Closing it from the value side means each of the 68 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 $4.1M 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 40 Leavenworth St:
Single-assumption flip points for 40 Leavenworth St, each holding the other three at their defaults.
| Circulation efficiencythe binding constraint — the least this building would need | 11% downto 72% |
|---|---|
| Average unit size | 12% upto 838 sq ft |
| Completed value per home | 12% downto $321K |
| Conversion cost per square foot | 19% upto $308/sq ft |
All four are sliders in the survey, where 40 Leavenworth St re-scores against your own numbers.
How it compares in Downtown San Francisco
40 Leavenworth St ranks 52nd 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 74% of them at its deepest interior point. On size it is the 151st 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 Tenderloin and the C-3-G zone
1st of 7 in Tenderloin, 1st of 22 zoned C-3-G — the comparison that shares its rules, rents and streets.
San Francisco places 7 of the screened buildings in Tenderloin. 40 Leavenworth St ranks 1st of them against a median score of 89, the top score in the group. 4 score 70 or more, their median deepest interior point is 34 ft from a facade against this building’s 34 ft, and together they would hold an estimated 499 homes.
22 of the screened buildings are zoned C-3-G. 40 Leavenworth St ranks 1st of them against a median score of 76, the top score in the group. 13 score 70 or more, their median deepest interior point is 51 ft from a facade against this building’s 34 ft, and together they would hold an estimated 2,588 homes.
Its nearest match in size: 137 New Montgomery St
The screened building closest to 40 Leavenworth St in converted floor area is 137 New Montgomery St: 64,287 sq ft over 6 stories, against 63,924 sq ft over 6 here.
The two land within a few points of each other — 92 here, 91 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 only with the modeled RESIDE grant. The two stand about 4,600 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 40 Leavenworth St $4.1M, 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 40 Leavenworth St
The 4 closest the screen also covers, from 480 ft away. They are the colored outlines on the plan at the top of this page.
- 1170 Market St7 stories · 100% daylit · 40 estimated homes · scores 89/100 (Strong candidate)about 480 ft away
- 1067 Market St6 stories · 100% daylit · 42 estimated homes · scores 89/100 (Strong candidate)about 510 ft away
- 1059 Market St6 stories · 100% daylit · 47 estimated homes · scores 90/100 (Strong candidate)about 570 ft away
- 2 Hyde St4 stories · 72% daylit · 71 estimated homes · scores 50/100 (Marginal)about 600 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.