207-211 Congress St
207-211 Congress St is a 32-story building in Downtown Boston with 82% of its floor area within daylight reach of a facade. This screen estimates 550 homes and scores it 84 out of 100 for office-to-residential conversion suitability.
MA-7 & MA-8 · Screened 2026-10-04 · Strong candidate
Also addressed as 100 High St: Boston’s address records place both on this one footprint.
Where 207-211 Congress St is
Its block in Downtown Boston, drawn from Boston's own building outlines and street centerlines.
- Already housing
- Not screened
- 207-211 Congress St
This building's conversion pencils at default assumptions without any subsidy.
Across its 31 residential floors this building carries 111,758 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 207-211 Congress St, 2026-10-04.
| Suitability scoreStrong candidate | 84 / 100 |
|---|---|
| Storiesfrom 380 ft aerial-survey height ÷ 12 ft floor-to-floor | 32 |
| Height bandsfloor plate by floor range, from the city's roof outlines | Floors 1–5: 40,167 sq ft · Floors 6–10: 36,388 sq ft · Floor 11: 26,213 sq ft · Floors 12–27: 13,700 sq ft · Floors 28–30: 11,122 sq ft · Floors 31–32: 3,286 sq ft |
| Floor platetypical floor, from the city outlines | 13,700 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 82% |
| Deepest interior pointviability threshold is 80 ft | 55 ft |
| Windowless coretypical floor; the building-wide total is in the text above | 2,321 sq ft |
| Estimated homesat 750 sq ft average | 550 |
| Conversion cost$360/sq ft all-in on 627,961 sq ft | $226.1M |
| Gap before grantpencils unsubsidized | -$16.8M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltBoston's own record of the construction year | 1930 |
| ZoningDowntown Boston | SKY |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
38 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 504 ft of exterior wall, and across 31 residential floors the building carries 21,000 ft of it in total, divided among the 550 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 17.7 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 67 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 207-211 Congress St scores 84 out of 100
Daylight efficiency 84, Interior depth 62, Scale 100, Finance 100 — each out of 100, then weighted.
Score components for 207-211 Congress St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency82% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 84 | 45% | 38.0 |
| Interior depthdeepest interior point 55 ft from a facade, scored from 80 ft down to 40 ft | 62 | 25% | 15.6 |
| Scale550 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| 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 interior depth, at 62 out of 100: deepest interior point 55 ft from a facade, scored from 80 ft down to 40 ft.
Built in 1930
Boston records this building as going up in 1930, which puts it in the interwar stock.
As a rule, steel or concrete frames with punched windows and plates still narrow enough for daylight to reach the middle, often with high ceilings. Among the most convertible stock there is, and the reason so many early conversions were of buildings this age. 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 82% daylight figure above deserves.
What the conversion would cost
$360 per square foot all-in across 627,961 sq ft of converted floor, or $226.1M in total — about $411K for each of the 550 homes.
All-in cost per square foot for 207-211 Congress 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 111,758 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 $442K a home, which for 550 homes is $242.8M.
What would have to be true
This one already clears the bar. The question is how much room it has before it stops.
At $442K a home, completed value covers the $226.1M of work with $16.8M to spare. Value per home would have to fall to $411K — 7% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $387 per square foot. Neither is a wide margin in a market that moves, but this building does not need a grant to work.
Each of these, moved on its own, would be enough to undo that for 207-211 Congress St:
Single-assumption flip points for 207-211 Congress St, each holding the other three at their defaults.
| Circulation efficiencythe binding constraint — the least this building would need | 11% downto 71% |
|---|---|
| Completed value per home | 11% downto $393K |
| Average unit size | 12% upto 843 sq ft |
| Conversion cost per square foot | 16% upto $303/sq ft |
All four are sliders in the survey, where 207-211 Congress St re-scores against your own numbers.
How it compares in Downtown Boston
207-211 Congress St ranks 62nd of the 96 buildings screened here, against a median score of 89.
Its floor plate is better lit than 34% of them, and shallower than 34% of them at its deepest interior point. On size it is the 24th largest by estimated homes. The full survey of all 96 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within the SKY zone
34th of 52 zoned SKY — the comparison that shares its rules, rents and streets.
52 of the screened buildings are zoned SKY. 207-211 Congress St ranks 34th of them against a median score of 88. 40 score 70 or more, their median deepest interior point is 51 ft from a facade against this building’s 55 ft, and together they would hold an estimated 19,019 homes. The group’s top scorer is 147 Milk St, at 100.
Its nearest match in size: 101 Federal St
The screened building closest to 207-211 Congress St in converted floor area is 101 Federal St: 585,149 sq ft over 31 stories, against 627,961 sq ft over 32 here.
207-211 Congress St scores 84 to its 93, and with the size held roughly equal most of that shortfall comes from daylight efficiency: 84 out of 100 here, 100 there (91% 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 pencils without a subsidy. The two stand about 400 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 207-211 Congress 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 207-211 Congress St
The 4 closest the screen also covers, from 220 ft away. They are the colored outlines on the plan at the top of this page.
- 99 High St34 stories · 70% daylit · 593 estimated homes · scores 61/100 (Worth a feasibility study)about 220 ft away
- 100 Federal St50 stories · 62% daylit · 1,164 estimated homes · scores 35/100 (Marginal)about 250 ft away
- 133 Federal St13 stories · 91% daylit · 117 estimated homes · scores 90/100 (Strong candidate)about 330 ft away
- 218-230 Congress St12 stories · 82% daylit · 202 estimated homes · scores 85/100 (Strong candidate)about 340 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.