1226 15th St
1226 15th St is a 6-story building in Greater Downtown Denver with 95% of its floor area within daylight reach of a facade. This screen estimates 134 homes and scores it 85 out of 100 for office-to-residential conversion suitability.
CO-1 · Screened 2026-09-19 · Strong candidate
Also addressed as 1228 15th St, 1400 Larimer St, 1402 Larimer St, 1404 Larimer St, 1406 Larimer St, 1408 Larimer St, 1410 Larimer St, 1412 Larimer St, 1414 Larimer St, 1418 Larimer St, 1420 Larimer St, 1422 Larimer St, 1424 Larimer St, 1426 Larimer St, 1428 Larimer St, 1430 Larimer St, 1436 Larimer St, 1440 Larimer St, 1442 Larimer St, 1450 Larimer St and 1460 Larimer St: Denver’s address records place all 22 on this one footprint.
Where 1226 15th St is
Its block in Greater Downtown Denver, drawn from Denver's own building outlines and street centerlines.
- Already housing
- Not screened
- 1226 15th St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Across its 5 residential floors this building carries 6,482 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment.
Read with caution. This footprint carries 22 street addresses across 42,076 sq ft, which usually means the city’s GIS has merged a block or complex into a single polygon rather than describing one convertible building.
Modeled conversion metrics for 1226 15th St, 2026-09-19.
| Suitability scoreStrong candidate | 85 / 100 |
|---|---|
| Storiesfrom 71 ft aerial-survey height ÷ 12 ft floor-to-floor | 6 |
| Height bandsfloor plate by floor range, from the city's roof outlines | Floors 1–2: 42,076 sq ft · Floor 3: 40,189 sq ft · Floor 4: 25,019 sq ft · Floors 5–6: 12,467 sq ft |
| Floor platetypical floor, from the city outlines | 42,076 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 95% |
| Deepest interior pointviability threshold is 80 ft | 55 ft |
| Windowless coretypical floor; the building-wide total is in the text above | 3,703 sq ft |
| Estimated homesat 750 sq ft average | 134 |
| Conversion cost$360/sq ft all-in on 132,219 sq ft | $47.6M |
| Gap before grantshortfall against completed value | $16.0M |
| Modeled RESIDE grantbelow the statutory cap | $8.0M |
| BuiltDenver does not publish a construction year with this data | — |
| ZoningUnion Station | D-C |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
43 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 1,432 ft of exterior wall, and across 5 residential floors the building carries 5,812 ft of it in total, divided among the 134 homes this screen estimates.
Its plate is elongated at 0.26: 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 26.8 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 1226 15th St scores 85 out of 100
Daylight efficiency 100, Interior depth 64, Scale 89, Finance 72 — each out of 100, then weighted.
Score components for 1226 15th St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency95% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 100 | 45% | 45.0 |
| Interior depthdeepest interior point 55 ft from a facade, scored from 80 ft down to 40 ft | 64 | 25% | 15.9 |
| Scale134 estimated homes, scored from 0 up to 150 | 89 | 15% | 13.4 |
| Financeremaining gap is 17% of conversion cost, scored from 60% down to 0% | 72 | 15% | 10.8 |
Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 64 out of 100: deepest interior point 55 ft from a facade, scored from 80 ft down to 40 ft.
What the conversion would cost
$360 per square foot all-in across 132,219 sq ft of converted floor, or $47.6M in total — about $355K for each of the 134 homes.
All-in cost per square foot for 1226 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 6,482 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 134 homes is $31.6M.
What would have to be true
A $16.0M gap before any grant, $7.9M after the modeled one. The smallest single change that would close it: average unit size 17% down.
The shortfall before any grant is $16.0M. Closing it from the value side means each of the 134 homes finishing at $355K rather than the $236K the model assumes — 51% more. Closing it from the cost side means getting all-in cost down from $360 to $239 per square foot.
A modeled RESIDE grant of $8.0M moves that threshold to $295K a home. That is still above the $236K assumed, leaving $7.9M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 1226 15th St, one alone would close the gap at:
Single-assumption flip points for 1226 15th St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 17% downto 625 sq ft |
|---|---|
| Circulation efficiency | 20% upto 96% |
| Conversion cost per square foot | 23% downto $200/sq ft |
| Completed value per home | 25% upto $295K |
All four are sliders in the survey, where 1226 15th St re-scores against your own numbers.
How it compares in Greater Downtown Denver
1226 15th St ranks 52nd of the 214 buildings screened here, against a median score of 72.
Its floor plate is better lit than 85% of them, and shallower than 57% of them at its deepest interior point. On size it is the 142nd 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 Union Station and the D-C zone
11th of 55 in Union Station, 14th of 72 zoned D-C — the comparison that shares its rules, rents and streets.
Denver places 55 of the screened buildings in Union Station. 1226 15th St ranks 11th of them against a median score of 69. 23 score 70 or more, their median deepest interior point is 61 ft from a facade against this building’s 55 ft, and together they would hold an estimated 13,167 homes. The group’s top scorer is 1600 17th St, at 95.
72 of the screened buildings are zoned D-C. 1226 15th St ranks 14th 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 55 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: 1705 17th St
The screened building closest to 1226 15th St in converted floor area is 1705 17th St: 131,440 sq ft over 7 stories, against 132,219 sq ft over 6 here.
1226 15th St scores 85 to its 47, and with the size held roughly equal most of that lead comes from daylight efficiency: 100 out of 100 here, 59 there (70% 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 2,300 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 1226 15th St $8.0M, 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 1226 15th St
The 4 closest the screen also covers, from 180 ft away. They are the colored outlines on the plan at the top of this page.
- 1475 Lawrence St8 stories · 94% daylit · 117 estimated homes · scores 87/100 (Strong candidate)about 180 ft away
- 1401 Lawrence St26 stories · 72% daylit · 462 estimated homes · scores 57/100 (Worth a feasibility study)about 180 ft away
- 1317 14th St5 stories · 83% daylit · 114 estimated homes · scores 69/100 (Worth a feasibility study)about 190 ft away
- 1250 14th St11 stories · 84% daylit · 145 estimated homes · scores 80/100 (Strong candidate)about 380 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.