25-31 West St

Where 25-31 West 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

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

The typical floor has 382 ft of exterior wall, and across 4 residential floors the building carries 1,530 ft of it in total, divided among the 31 homes this screen estimates.

Its plate is moderately compact at 0.63: 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 7.8 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 25-31 West St scores 88 out of 100

Daylight efficiency 100, Interior depth 100, Scale 21, Finance 100 — each out of 100, then weighted.

Most of what it earns comes from daylight efficiency, and what holds it back most is scale, at 21 out of 100: 31 estimated homes, scored from 0 up to 150.

Built in 1899

Boston records this building as going up in 1899, which puts it in the pre-1920 stock.

As a rule, the era that converts most readily: load-bearing masonry, small floor plates laid out before deep-plan offices were possible, operable windows and generous floor-to-floor heights. The usual obstacles are not daylight but hazardous materials, lifts and bringing structure up to current code. 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 100% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 29,496 sq ft of converted floor, or $10.6M in total — about $343K for each of the 31 homes.

That cost is charged across every converted square foot, including the circulation and service area that earns nothing directly. Against it the model sets a completed value of $442K a home, which for 31 homes is $13.7M.

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 $10.6M of work with $3.1M to spare. Value per home would have to fall to $343K — 22% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $464 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 25-31 West St:

All four are sliders in the survey, where 25-31 West St re-scores against your own numbers.

How it compares in Downtown Boston

25-31 West St ranks 52nd of the 96 buildings screened here, against a median score of 89.

Its floor plate is better lit than 100% of them, and shallower than 92% of them at its deepest interior point. On size it is the 96th 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-LOW-DT zone

22nd of 25 zoned SKY-LOW-DT — the comparison that shares its rules, rents and streets.

25 of the screened buildings are zoned SKY-LOW-DT. 25-31 West St ranks 22nd of them against a median score of 91. 24 score 70 or more, their median deepest interior point is 35 ft from a facade against this building’s 30 ft, and together they would hold an estimated 2,629 homes. The group’s top scorer is 36-44 Broad St, at 100.

Its nearest match in size: 105-111 Summer St

The screened building closest to 25-31 West St in converted floor area is 105-111 Summer St: 31,073 sq ft over 6 stories, against 29,496 sq ft over 5 here.

The two land within a few points of each other — 88 here, 88 there — so at this size the screen reads them as much the same prospect. On the money they sit in the same place: each pencils without a subsidy. The two stand about 1,300 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 25-31 West St $1.9M, 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 25-31 West St

The 4 closest the screen also covers, from 260 ft away. They are the colored outlines on the plan at the top of this page.

• 150 Tremont St
  22 stories · 89% daylit · already a condominium building
  about 260 ft away
• 60-70 Temple Pl
  7 stories · 95% daylit · 50 estimated homes · scores 89/100 (Strong candidate)
  about 310 ft away
• 28-38 Winter St
  14 stories · 95% daylit · 106 estimated homes · scores 95/100 (Strong candidate)
  about 380 ft away
• 1 Avenue De Lafayette
  22 stories · 59% daylit · 721 estimated homes · scores 35/100 (Marginal)
  about 510 ft away