6-6B Beacon St

Where 6-6B Beacon 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

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

The typical floor has 506 ft of exterior wall, and across 9 residential floors the building carries 4,557 ft of it in total, divided among the 92 homes this screen estimates.

Its plate is moderately compact at 0.47: 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 10.2 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 6-6B Beacon St scores 94 out of 100

Daylight efficiency 100, Interior depth 100, Scale 61, 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 61 out of 100: 92 estimated homes, scored from 0 up to 150.

Built in 1910

Boston records this building as going up in 1910, 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 86,946 sq ft of converted floor, or $31.3M in total — about $340K for each of the 92 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 92 homes is $40.6M.

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 $31.3M of work with $9.3M to spare. Value per home would have to fall to $340K — 23% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $467 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 6-6B Beacon St:

All four are sliders in the survey, where 6-6B Beacon St re-scores against your own numbers.

How it compares in Downtown Boston

6-6B Beacon St ranks 16th 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 97% of them at its deepest interior point. On size it is the 65th 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 PEMBERTON SQUARE PROTECTION AREA zone

1st of 7 zoned PEMBERTON SQUARE PROTECTION AREA — the comparison that shares its rules, rents and streets.

7 of the screened buildings are zoned PEMBERTON SQUARE PROTECTION AREA. 6-6B Beacon St ranks 1st of them against a median score of 79, the top score in the group. 5 score 70 or more, their median deepest interior point is 60 ft from a facade against this building’s 28 ft, and together they would hold an estimated 2,645 homes.

Its nearest match in size: 42-60 Federal St

The screened building closest to 6-6B Beacon St in converted floor area is 42-60 Federal St: 82,690 sq ft over 10 stories, against 86,946 sq ft over 10 here.

6-6B Beacon St scores 94 to its 89, and with the size held roughly equal most of that lead comes from interior depth: 100 out of 100 here, 85 there (deepest interior point 46 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 1,600 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 6-6B Beacon St $5.5M, 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 6-6B Beacon 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.

• 69-81 Tremont St
  14 stories · 72% daylit · 258 estimated homes · scores 64/100 (Worth a feasibility study)
  about 150 ft away
• 12-14A Beacon St
  9 stories · 100% daylit · 85 estimated homes · scores 94/100 (Strong candidate)
  about 220 ft away
• 21-23 Beacon St
  10 stories · 83% daylit · already a condominium building
  about 250 ft away
• 1 Beacon St
  42 stories · 65% daylit · 881 estimated homes · scores 55/100 (Worth a feasibility study)
  about 260 ft away