218-230 Congress St

Where 218-230 Congress St is

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

The plan: window line, shape and floor rhythm

35 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.

The typical floor has 651 ft of exterior wall, and across 11 residential floors the building carries 7,157 ft of it in total, divided among the 202 homes this screen estimates.

Its plate is moderately compact at 0.62: 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 18.4 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 218-230 Congress St scores 85 out of 100

Daylight efficiency 85, Interior depth 68, Scale 100, Finance 100 — each out of 100, then weighted.

Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 68 out of 100: deepest interior point 53 ft from a facade, scored from 80 ft down to 40 ft.

Built in 1936

Boston records this building as going up in 1936, 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 230,180 sq ft of converted floor, or $82.9M in total — about $410K for each of the 202 homes.

That cost is charged across every converted square foot, including the 40,579 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 202 homes is $89.2M.

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 $82.9M of work with $6.3M to spare. Value per home would have to fall to $410K — 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 218-230 Congress St:

All four are sliders in the survey, where 218-230 Congress St re-scores against your own numbers.

How it compares in Downtown Boston

218-230 Congress St ranks 58th of the 96 buildings screened here, against a median score of 89.

Its floor plate is better lit than 35% of them, and shallower than 41% of them at its deepest interior point. On size it is the 43rd 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

30th of 52 zoned SKY — the comparison that shares its rules, rents and streets.

52 of the screened buildings are zoned SKY. 218-230 Congress St ranks 30th 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 53 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: 147 Milk St

The screened building closest to 218-230 Congress St in converted floor area is 147 Milk St: 242,850 sq ft over 10 stories, against 230,180 sq ft over 12 here.

218-230 Congress St scores 85 to its 100, and with the size held roughly equal most of that shortfall comes from interior depth: 68 out of 100 here, 100 there (deepest interior point 32 ft from a facade, scored from 80 ft down to 40 ft). On the money they sit in the same place: each pencils without a subsidy. The two stand about 1,000 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 218-230 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 218-230 Congress 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.

• 99 High St
  34 stories · 70% daylit · 593 estimated homes · scores 61/100 (Worth a feasibility study)
  about 200 ft away
• 207-211 Congress St
  32 stories · 82% daylit · 550 estimated homes · scores 84/100 (Strong candidate)
  about 340 ft away
• 185 Franklin St
  29 stories · 54% daylit · 584 estimated homes · scores 35/100 (Marginal)
  about 350 ft away
• 100 Federal St
  50 stories · 62% daylit · 1,164 estimated homes · scores 35/100 (Marginal)
  about 520 ft away