175 Federal St

Where 175 Federal 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

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 480 ft of exterior wall, and across 19 residential floors the building carries 8,614 ft of it in total, divided among the 232 homes this screen estimates.

Its plate is compact at 0.83: close to a square or a circle, the most efficient envelope an office can have and the least generous one for apartments: little perimeter to divide among homes. How window line and plate shape are measured.

At the model’s 750 sq ft average, the plan works out at about 12.2 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 175 Federal St scores 87 out of 100

Daylight efficiency 86, Interior depth 73, 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 73 out of 100: deepest interior point 51 ft from a facade, scored from 80 ft down to 40 ft.

Built in 1977

Boston records this building as going up in 1977, which puts it in the late-modern stock.

As a rule, typically the hardest to convert: the deepest plates of any era, large central cores, and floor-to-floor heights tight enough that running residential drainage under a ceiling can be the thing that ends a project. 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 83% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 262,123 sq ft of converted floor, or $94.4M in total — about $407K for each of the 232 homes.

That cost is charged across every converted square foot, including the 44,123 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 232 homes is $102.4M.

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 $94.4M of work with $8.1M to spare. Value per home would have to fall to $407K — 8% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $391 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 175 Federal St:

All four are sliders in the survey, where 175 Federal St re-scores against your own numbers.

How it compares in Downtown Boston

175 Federal St ranks 55th of the 96 buildings screened here, against a median score of 89.

Its floor plate is better lit than 40% of them, and shallower than 45% of them at its deepest interior point. On size it is the 42nd 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

28th of 52 zoned SKY — the comparison that shares its rules, rents and streets.

52 of the screened buildings are zoned SKY. 175 Federal St ranks 28th 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 51 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: 75-101 Federal St

The screened building closest to 175 Federal St in converted floor area is 75-101 Federal St: 271,598 sq ft over 21 stories, against 262,123 sq ft over 20 here.

175 Federal St scores 87 to its 96, and with the size held roughly equal most of that shortfall comes from daylight efficiency: 86 out of 100 here, 98 there (89% 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 700 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 175 Federal 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 175 Federal St

The 4 closest the screen also covers, from 160 ft away. They are the colored outlines on the plan at the top of this page.

• 172-180 Federal St
  7 stories · 91% daylit · 63 estimated homes · scores 88/100 (Strong candidate)
  about 160 ft away
• 155 Federal St
  18 stories · 92% daylit · 191 estimated homes · scores 95/100 (Strong candidate)
  about 180 ft away
• 669-671 Atlantic Ave
  49 stories · 67% daylit · 1,019 estimated homes · scores 63/100 (Worth a feasibility study)
  about 350 ft away
• 100 Summer St
  35 stories · 74% daylit · 856 estimated homes · scores 67/100 (Worth a feasibility study)
  about 350 ft away