1184 15th St
1184 15th St is a 49-story building in Greater Downtown Denver with 75% of its floor area within daylight reach of a facade. This screen estimates 876 homes and scores it 66 out of 100 for office-to-residential conversion suitability.
CO-1 · Screened 2026-09-19 · Worth a feasibility study
Also addressed as 1455 Arapahoe St: Denver’s address records place both on this one footprint.
Where 1184 15th St is
Its block in Greater Downtown Denver, drawn from Denver's own building outlines and street centerlines.
- Already housing
- Not screened
- 1184 15th St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Across its 48 residential floors this building carries 268,702 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 1184 15th St, 2026-09-19.
| Suitability scoreWorth a feasibility study | 66 / 100 |
|---|---|
| Storiesfrom 584 ft aerial-survey height ÷ 12 ft floor-to-floor | 49 |
| Height bandsfloor plate by floor range, from the city's roof outlines | Floors 1–11: 33,580 sq ft · Floors 12–13: 30,974 sq ft · Floors 14–44: 19,595 sq ft · Floors 45–49: 17,029 sq ft |
| Floor platetypical floor, from the city outlines | 19,595 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 75% |
| Deepest interior pointviability threshold is 80 ft | 55 ft |
| Windowless coretypical floor; the building-wide total is in the text above | 4,341 sq ft |
| Estimated homesat 750 sq ft average | 876 |
| Conversion cost$360/sq ft all-in on 1,090,331 sq ft | $392.5M |
| Gap before grantshortfall against completed value | $185.8M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltDenver does not publish a construction year with this data | — |
| ZoningCBD | D-TD |
| 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 602 ft of exterior wall, and across 48 residential floors the building carries 32,116 ft of it in total, divided among the 876 homes this screen estimates.
Its plate is moderately compact at 0.68: 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 18.3 homes per floor. Its floors are not alike, though: the typical floor's deepest interior point is 55 ft from a facade, while its worst floor reaches 70 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 1184 15th St scores 66 out of 100
Daylight efficiency 71, Interior depth 62, Scale 100, Finance 25 — each out of 100, then weighted.
Score components for 1184 15th St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency75% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 71 | 45% | 31.8 |
| Interior depthdeepest interior point 55 ft from a facade, scored from 80 ft down to 40 ft | 62 | 25% | 15.4 |
| Scale876 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 45% of conversion cost, scored from 60% down to 0% | 25 | 15% | 3.8 |
Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 25 out of 100: remaining gap is 45% of conversion cost, scored from 60% down to 0%.
What the conversion would cost
$360 per square foot all-in across 1,090,331 sq ft of converted floor, or $392.5M in total — about $448K for each of the 876 homes.
All-in cost per square foot for 1184 15th 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 268,702 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 876 homes is $206.7M.
What would have to be true
A $185.8M gap before any grant, $175.8M after the modeled one. The smallest single change that would close it: average unit size 46% down.
The shortfall before any grant is $185.8M. Closing it from the value side means each of the 876 homes finishing at $448K rather than the $236K the model assumes — 90% more. Closing it from the cost side means getting all-in cost down from $360 to $190 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $437K a home. That is still above the $236K assumed, leaving $175.8M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 1184 15th St, one alone would close the gap at:
Single-assumption flip points for 1184 15th St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 46% downto 405 sq ft |
|---|---|
| Conversion cost per square foot | 62% downto $99/sq ft |
| Completed value per home | 85% upto $437K |
All four are sliders in the survey, where 1184 15th St re-scores against your own numbers.
How it compares in Greater Downtown Denver
1184 15th St ranks 137th of the 214 buildings screened here, against a median score of 72.
Its floor plate is better lit than 30% of them, and shallower than 55% of them at its deepest interior point. On size it is the 15th 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-TD zone
50th of 75 in CBD, 12th of 20 zoned D-TD — the comparison that shares its rules, rents and streets.
Denver places 75 of the screened buildings in CBD. 1184 15th St ranks 50th 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 55 ft, and together they would hold an estimated 33,698 homes. The group’s top scorer is 918 17th St, at 97.
20 of the screened buildings are zoned D-TD. 1184 15th St ranks 12th of them against a median score of 69. 10 score 70 or more, their median deepest interior point is 57 ft from a facade against this building’s 55 ft, and together they would hold an estimated 8,599 homes. The group’s top scorer is 918 17th St, at 97.
Its nearest match in size: 707 17th St
The screened building closest to 1184 15th St in converted floor area is 707 17th St: 1,055,987 sq ft over 44 stories, against 1,090,331 sq ft over 49 here.
1184 15th St scores 66 to its 62, and with the size held roughly equal most of that lead comes from daylight efficiency: 71 out of 100 here, 66 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 2,000 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 1184 15th 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 1184 15th St
The 4 closest the screen also covers, from 200 ft away. They are the colored outlines on the plan at the top of this page.
- 1111 14th St46 stories · 79% daylit · 614 estimated homes · scores 74/100 (Strong candidate)about 200 ft away
- 1475 Lawrence St8 stories · 94% daylit · 117 estimated homes · scores 87/100 (Strong candidate)about 260 ft away
- 1401 Lawrence St26 stories · 72% daylit · 462 estimated homes · scores 57/100 (Worth a feasibility study)about 350 ft away
- 1111 15th St19 stories · 86% daylit · 562 estimated homes · scores 83/100 (Strong candidate)about 360 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.