1801 California St
1801 California St is a 59-story building in Greater Downtown Denver with 67% of its floor area within daylight reach of a facade. This screen estimates 1,381 homes and scores it 52 out of 100 for office-to-residential conversion suitability.
CO-1 · Screened 2026-09-19 · Worth a feasibility study
Also addressed as 1847 California St: Denver’s address records place both on this one footprint.
Where 1801 California St is
Its block in Greater Downtown Denver, drawn from Denver's own building outlines and street centerlines.
- Already housing
- Not screened
- 1801 California St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Across its 58 residential floors this building carries 652,021 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment.
Modeled conversion metrics for 1801 California St, 2026-09-19.
| Suitability scoreWorth a feasibility study | 52 / 100 |
|---|---|
| Storiesfrom 713 ft aerial-survey height ÷ 12 ft floor-to-floor | 59 |
| Height bandsfloor plate by floor range, from the city's roof outlines | Floors 1–3: 87,595 sq ft · Floors 4–5: 83,867 sq ft · Floors 6–8: 83,040 sq ft · Floor 9: 81,073 sq ft · Floors 10–11: 36,916 sq ft · Floors 12–16: 34,646 sq ft · Floors 17–30: 28,773 sq ft · Floors 31–56: 22,362 sq ft · Floors 57–59: 14,154 sq ft |
| Floor platetypical floor, from the city outlines | 22,362 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 67% |
| Deepest interior pointviability threshold is 80 ft | 62 ft |
| Windowless coretypical floor; the building-wide total is in the text above | 6,225 sq ft |
| Estimated homesat 750 sq ft average | 1,381 |
| Conversion cost$360/sq ft all-in on 1,946,868 sq ft | $700.9M |
| Gap before grantshortfall against completed value | $375.0M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltDenver does not publish a construction year with this data | — |
| ZoningCBD | D-C |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
33 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 579 ft of exterior wall, and across 58 residential floors the building carries 45,691 ft of it in total, divided among the 1,381 homes this screen estimates.
Its plate is compact at 0.84: close to a square or a circle, the most efficient envelope an office can have and the least generous one for apartments: little perimeter to divide among homes. How window line and plate shape are measured.
At the model’s 750 sq ft average, the plan works out at about 23.8 homes per floor. Its floors are not alike, though: the typical floor's deepest interior point is 62 ft from a facade, while its worst floor reaches 88 ft. The score follows the typical floor, so a podium that could not hold a bedroom does not by itself sink a slim tower above it — but it is there, and it is part of what would have to be drawn around.
Why 1801 California St scores 52 out of 100
Daylight efficiency 53, Interior depth 45, Scale 100, Finance 13 — each out of 100, then weighted.
Score components for 1801 California St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency67% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 53 | 45% | 23.9 |
| Interior depthdeepest interior point 62 ft from a facade, scored from 80 ft down to 40 ft | 45 | 25% | 11.2 |
| Scale1381 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 52% of conversion cost, scored from 60% down to 0% | 13 | 15% | 2.0 |
Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 13 out of 100: remaining gap is 52% of conversion cost, scored from 60% down to 0%.
What the conversion would cost
$360 per square foot all-in across 1,946,868 sq ft of converted floor, or $700.9M in total — about $508K for each of the 1,381 homes.
All-in cost per square foot for 1801 California St: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/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 | $360/sq ft |
That cost is charged across every converted square foot, including the 652,021 sq ft of windowless core, which has to be gutted, re-plumbed and sprinklered like the rest of the building and then earns nothing. Against it the model sets a completed value of $236K a home, which for 1,381 homes is $325.9M.
What would have to be true
A $375.0M gap before any grant, $365.0M after the modeled one. The smallest single change that would close it: average unit size 53% down.
The shortfall before any grant is $375.0M. Closing it from the value side means each of the 1,381 homes finishing at $508K rather than the $236K the model assumes — 115% more. Closing it from the cost side means getting all-in cost down from $360 to $167 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $500K a home. That is still above the $236K assumed, leaving $365.0M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 1801 California St, one alone would close the gap at:
Single-assumption flip points for 1801 California St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 53% downto 354 sq ft |
|---|---|
| Conversion cost per square foot | 72% downto $73/sq ft |
| Completed value per home | 112% upto $500K |
All four are sliders in the survey, where 1801 California St re-scores against your own numbers.
How it compares in Greater Downtown Denver
1801 California St ranks 190th of the 214 buildings screened here, against a median score of 72.
Its floor plate is better lit than 7% of them, and shallower than 28% of them at its deepest interior point. On size it is the 5th largest by estimated homes. The full survey of all 214 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within CBD and the D-C zone
66th of 75 in CBD, 68th of 72 zoned D-C — the comparison that shares its rules, rents and streets.
Denver places 75 of the screened buildings in CBD. 1801 California St ranks 66th of them against a median score of 71. 40 score 70 or more, their median deepest interior point is 56 ft from a facade against this building’s 62 ft, and together they would hold an estimated 33,698 homes. The group’s top scorer is 918 17th St, at 97.
72 of the screened buildings are zoned D-C. 1801 California St ranks 68th of them against a median score of 73. 39 score 70 or more, their median deepest interior point is 57 ft from a facade against this building’s 62 ft, and together they would hold an estimated 32,881 homes. The group’s top scorer is 721 19th St, at 95.
Its nearest match in size: 370 17th St
The screened building closest to 1801 California St in converted floor area is 370 17th St: 1,504,502 sq ft over 60 stories, against 1,946,868 sq ft over 59 here.
1801 California St scores 52 to its 57, and with the size held roughly equal most of that shortfall comes from daylight efficiency: 53 out of 100 here, 62 there (71% 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 1,600 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 1801 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 1801 California St
The 4 closest the screen also covers, from 350 ft away. They are the colored outlines on the plan at the top of this page.
- 707 17th St44 stories · 73% daylit · 822 estimated homes · scores 62/100 (Worth a feasibility study)about 350 ft away
- 1823 Stout St8 stories · 76% daylit · 269 estimated homes · scores 78/100 (Strong candidate)about 360 ft away
- 721 19th St8 stories · 100% daylit · 347 estimated homes · scores 95/100 (Strong candidate)about 460 ft away
- 1999 N Broadway46 stories · 91% daylit · 802 estimated homes · scores 83/100 (Strong candidate)about 500 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.