550 15th St

550 15th St is a 17-story building in Greater Downtown Denver with 78% of its floor area within daylight reach of a facade. This screen estimates 253 homes and scores it 70 out of 100 for office-to-residential conversion suitability.

CO-1 · Screened 2026-09-19 · Worth a feasibility study

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Where 550 15th St is

Its block in Greater Downtown Denver, drawn from Denver's own building outlines and street centerlines.

Suitability score

0–29

30–49

50–69

70–100

Already housing
Not screened
550 15th St

550 15th St and the 1,000 ft of Greater Downtown Denver around it. The streets are drawn at the width of the right-of-way they run down, sidewalks included, and named, and every building on these blocks is drawn. What is left open and stippled is neither: a surface lot, a plaza or a vacant parcel. The screened buildings are colored by the ramp above, the same one the district map uses, carry their score, and each is a link to its own page. Each casts a shadow as long as its measured height lets it, so towers stand out from the low buildings around them; the unscreened buildings have no measured height and cast none. 550 15th St is outlined in its own score color at the outline it covers at ground level. Dashed inside it is the typical floor, the one the floor-plate figure below draws, because this building steps back as it rises. Its windowless core is hatched. The inset places it among every building the screen covers.

Typical floor plan: 78% of the building’s floor area sits within daylight reach of a facade; the drawing shows its typical floor, where the share is 77%. The shading is daylight, darkest at the windows and gone 35 ft in. The hatched area is windowless core: 4,747 sq ft per typical floor that must be renovated but can never be rented as an apartment. The dimension marks the deepest interior point, 56 ft from the nearest window. A–A is where the section beside it is cut.

Section A–A: cut across the depth of the plate, through the middle of the core. Daylight reaches 35 ft in from every facade, fading as it goes, and the hatched stripe left between the lit edges is floor that gets converted and can never be rented: 4,747 sq ft on the floor the screen scores, and 68,296 sq ft over 16 residential floors. The steps are where the building sets back as it rises. The shaded ground floor is converted like the rest and counted as no homes.

This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.

Across its 16 residential floors this building carries 68,296 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 550 15th St, 2026-09-19.

Suitability scoreWorth a feasibility study	70 / 100
Storiesfrom 204 ft aerial-survey height ÷ 12 ft floor-to-floor	17
Height bandsfloor plate by floor range, from the city's roof outlines	Floors 1–2: 22,202 sq ft · Floors 3–15: 20,595 sq ft · Floors 16–17: 8,226 sq ft
Floor platetypical floor, from the city outlines	20,595 sq ft
Daylight efficiencyshare within 35 ft of a facade	78%
Deepest interior pointviability threshold is 80 ft	56 ft
Windowless coretypical floor; the building-wide total is in the text above	4,747 sq ft
Estimated homesat 750 sq ft average	253
Conversion cost$360/sq ft all-in on 306,386 sq ft	$110.3M
Gap before grantshortfall against completed value	$50.6M
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

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 615 ft of exterior wall, and across 16 residential floors the building carries 9,361 ft of it in total, divided among the 253 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 15.8 homes per floor. Its floors are not alike, though: the typical floor's deepest interior point is 56 ft from a facade, while its worst floor reaches 62 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 550 15th St scores 70 out of 100

Daylight efficiency 75, Interior depth 60, Scale 100, Finance 39 — each out of 100, then weighted.

Score components for 550 15th St. Points are the subscore times its weight.

Component	Subscore	Weight	Points
Daylight efficiency78% of the floor area within 35 ft of a facade, scored from 40% up to 90%	75	45%	33.9
Interior depthdeepest interior point 56 ft from a facade, scored from 80 ft down to 40 ft	60	25%	15.1
Scale253 estimated homes, scored from 0 up to 150	100	15%	15.0
Financeremaining gap is 37% of conversion cost, scored from 60% down to 0%	39	15%	5.8

Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 39 out of 100: remaining gap is 37% of conversion cost, scored from 60% down to 0%.

What the conversion would cost

$360 per square foot all-in across 306,386 sq ft of converted floor, or $110.3M in total — about $436K for each of the 253 homes.

All-in cost per square foot for 550 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 68,296 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 253 homes is $59.7M.

What would have to be true

A $50.6M gap before any grant, $40.6M after the modeled one. The smallest single change that would close it: average unit size 40% down.

The shortfall before any grant is $50.6M. Closing it from the value side means each of the 253 homes finishing at $436K rather than the $236K the model assumes — 85% more. Closing it from the cost side means getting all-in cost down from $360 to $195 per square foot.

A modeled RESIDE grant of $10.0M moves that threshold to $396K a home. That is still above the $236K assumed, leaving $40.6M uncovered, which is why the grant does not unlock this one.

Nor do all four levers have to move. For 550 15th St, one alone would close the gap at:

Single-assumption flip points for 550 15th St, each holding the other three at their defaults.

Average unit sizethe binding constraint — the least this building would need	40% downto 448 sq ft
Conversion cost per square foot	51% downto $128/sq ft
Completed value per home	68% upto $396K

All four are sliders in the survey, where 550 15th St re-scores against your own numbers.

How it compares in Greater Downtown Denver

550 15th St ranks 115th of the 214 buildings screened here, against a median score of 72.

Its floor plate is better lit than 35% of them, and shallower than 54% of them at its deepest interior point. On size it is the 85th 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

41st of 75 in CBD, 40th of 72 zoned D-C — the comparison that shares its rules, rents and streets.

Denver places 75 of the screened buildings in CBD. 550 15th St ranks 41st 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 56 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. 550 15th St ranks 40th 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 56 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: 1401 17th St

The screened building closest to 550 15th St in converted floor area is 1401 17th St: 315,586 sq ft over 17 stories, against 306,386 sq ft over 17 here.

The two land within a few points of each other — 70 here, 69 there — so at this size the screen reads them as much the same prospect. On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 3,300 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 550 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 550 15th St

The 4 closest the screen also covers, from 150 ft away. They are the colored outlines on the plan at the top of this page.

500 15th St
8 stories · 88% daylit · 71 estimated homes · scores 77/100 (Strong candidate)
about 150 ft away
1400 Welton St
11 stories · 84% daylit · 145 estimated homes · scores 75/100 (Strong candidate)
about 220 ft away
650 15th St
37 stories · 71% daylit · 814 estimated homes · scores 71/100 (Strong candidate)
about 290 ft away
439 14th St
17 stories · 85% daylit · 239 estimated homes · scores 88/100 (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.