11 Avenue De Lafayette
11 Avenue De Lafayette is a 6-story building in Downtown Boston with 99% of its floor area within daylight reach of a facade. This screen estimates 61 homes and scores it 91 out of 100 for office-to-residential conversion suitability.
MA-7 & MA-8 · Screened 2026-10-04 · Strong candidate
Where 11 Avenue De Lafayette is
Its block in Downtown Boston, drawn from Boston's own building outlines and street centerlines.
- Already housing
- Not screened
- 11 Avenue De Lafayette
This building's conversion pencils at default assumptions without any subsidy.
Every floor carries 77 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment. Across 5 residential floors that is 383 sq ft of cost carrying no revenue.
Modeled conversion metrics for 11 Avenue De Lafayette, 2026-10-04.
| Suitability scoreStrong candidate | 91 / 100 |
|---|---|
| Storiesfrom 71 ft aerial-survey height ÷ 12 ft floor-to-floor | 6 |
| Floor plateper floor, from the city footprint | 11,555 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 99% |
| Deepest interior pointviability threshold is 80 ft | 37 ft |
| Windowless coreper floor — renovated but never rentable | 77 sq ft |
| Estimated homesat 750 sq ft average | 61 |
| Conversion cost$360/sq ft all-in on 57,775 sq ft | $20.8M |
| Gap before grantpencils unsubsidized | -$6.1M |
| Modeled RESIDE grantbelow the statutory cap | $3.7M |
| BuiltBoston's own record of the construction year | 1899 |
| ZoningDowntown Boston | SKY |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
42 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 518 ft of exterior wall, and across 5 residential floors the building carries 2,588 ft of it in total, divided among the 61 homes this screen estimates.
Its plate is moderately compact at 0.54: 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 12.2 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 11 Avenue De Lafayette scores 91 out of 100
Daylight efficiency 100, Interior depth 100, Scale 41, Finance 100 — each out of 100, then weighted.
Score components for 11 Avenue De Lafayette. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency99% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 100 | 45% | 45.0 |
| Interior depthdeepest interior point 37 ft from a facade, scored from 80 ft down to 40 ft | 100 | 25% | 25.0 |
| Scale61 estimated homes, scored from 0 up to 150 | 41 | 15% | 6.1 |
| Financecompleted value covers conversion cost with 47% to spare, which tops out the component | 100 | 15% | 15.0 |
Most of what it earns comes from daylight efficiency, and what holds it back most is scale, at 41 out of 100: 61 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 99% daylight figure above deserves.
What the conversion would cost
$360 per square foot all-in across 57,775 sq ft of converted floor, or $20.8M in total — about $341K for each of the 61 homes.
All-in cost per square foot for 11 Avenue De Lafayette: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/sq ft |
|---|---|
| Plumbing risers to every unit | $40/sq ft |
| Operable windows and glazing | $30/sq ft |
| Additional egress stair | $18/sq ft |
| Fire sprinklers (NFPA 13R) | $12/sq ft |
| All-in | $360/sq ft |
That cost is charged across every converted square foot, including the 383 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 61 homes is $26.9M.
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 $20.8M of work with $6.1M to spare. Value per home would have to fall to $341K — 23% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $466 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 11 Avenue De Lafayette:
Single-assumption flip points for 11 Avenue De Lafayette, each holding the other three at their defaults.
| Circulation efficiencythe binding constraint — the least this building would need | 31% downto 55% |
|---|---|
| Completed value per home | 36% downto $281K |
| Average unit size | 46% upto 1,093 sq ft |
| Conversion cost per square foot | 65% upto $430/sq ft |
All four are sliders in the survey, where 11 Avenue De Lafayette re-scores against your own numbers.
How it compares in Downtown Boston
11 Avenue De Lafayette ranks 29th of the 96 buildings screened here, against a median score of 89.
Its floor plate is better lit than 76% of them, and shallower than 76% of them at its deepest interior point. On size it is the 82nd 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
13th of 52 zoned SKY — the comparison that shares its rules, rents and streets.
52 of the screened buildings are zoned SKY. 11 Avenue De Lafayette ranks 13th 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 37 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: 100 City Hall Plz
The screened building closest to 11 Avenue De Lafayette in converted floor area is 100 City Hall Plz: 54,738 sq ft over 7 stories, against 57,775 sq ft over 6 here.
The two land within a few points of each other — 91 here, 91 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 2,500 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 11 Avenue De Lafayette $3.7M, 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 11 Avenue De Lafayette
The 4 closest the screen also covers, from 80 ft away. They are the colored outlines on the plan at the top of this page.
- 62-74 Essex St8 stories · 96% daylit · 70 estimated homes · scores 90/100 (Strong candidate)about 80 ft away
- 99 Chauncy St11 stories · 97% daylit · 178 estimated homes · scores 98/100 (Strong candidate)about 180 ft away
- 588-622 Washington St8 stories · 53% daylit · 199 estimated homes · scores 35/100 (Marginal)about 390 ft away
- 22-40 Chauncy St11 stories · 86% daylit · 195 estimated homes · scores 88/100 (Strong candidate)about 400 ft away
A screen, not a feasibility study, from outlines and heights rather than plans: the method and how to correct a figure. If you know this building’s interior, you know what this model cannot see.