315-333 Washington St

Where 315-333 Washington 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

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

The typical floor has 962 ft of exterior wall, and across 7 residential floors the building carries 6,595 ft of it in total, divided among the 160 homes this screen estimates.

Its plate is elongated at 0.29: a slab or an L, which is why so much of the floor lies within reach of a window: the outline buys daylight that a square plan of the same area would not. How window line and plate shape are measured.

At the model’s 750 sq ft average, the plan works out at about 22.9 homes per floor. Its floors are not alike, though: the typical floor's deepest interior point is 33 ft from a facade, while its worst floor reaches 58 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 315-333 Washington St scores 100 out of 100

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

Every component scores at or near full marks, so nothing in the geometry or the pro-forma is holding this one back — daylight efficiency carries the most weight of the four.

Built in 1999

Boston records this building as going up in 1999, which puts it in the modern stock.

As a rule, newer systems and better structure, but usually built deep and sealed for office use, and rarely cheap enough to buy at a price that lets a conversion pencil. 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 97% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 155,113 sq ft of converted floor, or $55.8M in total — about $349K for each of the 160 homes.

That cost is charged across every converted square foot, including the 4,670 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 160 homes is $70.6M.

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 $55.8M of work with $14.8M to spare. Value per home would have to fall to $349K — 21% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $455 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 315-333 Washington St:

All four are sliders in the survey, where 315-333 Washington St re-scores against your own numbers.

How it compares in Downtown Boston

315-333 Washington St ranks 1st of the 96 buildings screened here, against a median score of 89.

Its floor plate is better lit than 70% of them, and shallower than 84% of them at its deepest interior point. On size it is the 50th 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

1st 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. 315-333 Washington St ranks 1st of them against a median score of 91, the top score in the group. 24 score 70 or more, their median deepest interior point is 35 ft from a facade against this building’s 33 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: 157-175 Devonshire St

The screened building closest to 315-333 Washington St in converted floor area is 157-175 Devonshire St: 156,162 sq ft over 11 stories, against 155,113 sq ft over 8 here.

The two land within a few points of each other — 100 here, 100 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 500 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 315-333 Washington St $9.6M, 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 315-333 Washington St

The 4 closest the screen also covers, from 130 ft away. They are the colored outlines on the plan at the top of this page.

• 10-30 School St
  9 stories · 86% daylit · 120 estimated homes · scores 81/100 (Strong candidate)
  about 130 ft away
• 23-29 School St
  7 stories · 100% daylit · 43 estimated homes · scores 89/100 (Strong candidate)
  about 280 ft away
• 31-39 Bromfield St
  11 stories · 100% daylit · 64 estimated homes · scores 91/100 (Strong candidate)
  about 310 ft away
• 32-38 Bromfield St
  6 stories · 100% daylit · 44 estimated homes · scores 89/100 (Strong candidate)
  about 360 ft away