40-62 Franklin St
40-62 Franklin St is a 5-story building in Downtown Boston with 85% of its floor area within daylight reach of a facade. This screen estimates 47 homes and scores it 76 out of 100 for office-to-residential conversion suitability.
MA-7 & MA-8 · Screened 2026-10-04 · Strong candidate
Also addressed as 60 Franklin St: Boston’s address records place both on this one footprint.
Where 40-62 Franklin St is
Its block in Downtown Boston, drawn from Boston's own building outlines and street centerlines.
- Already housing
- Not screened
- 40-62 Franklin St
This building's conversion pencils at default assumptions without any subsidy.
Every floor carries 1,927 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment. Across 4 residential floors that is 7,707 sq ft of cost carrying no revenue.
Modeled conversion metrics for 40-62 Franklin St, 2026-10-04.
| Suitability scoreStrong candidate | 76 / 100 |
|---|---|
| Storiesfrom 62 ft aerial-survey height ÷ 12 ft floor-to-floor | 5 |
| Floor plateper floor, from the city footprint | 12,960 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 85% |
| Deepest interior pointviability threshold is 80 ft | 55 ft |
| Windowless coreper floor — renovated but never rentable | 1,927 sq ft |
| Estimated homesat 750 sq ft average | 47 |
| Conversion cost$360/sq ft all-in on 51,840 sq ft | $18.7M |
| Gap before grantpencils unsubsidized | -$2.1M |
| Modeled RESIDE grantbelow the statutory cap | $2.8M |
| BuiltBoston's own record of the construction year | 1999 |
| ZoningDowntown Boston | SKY |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
38 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 449 ft of exterior wall, and across 4 residential floors the building carries 1,798 ft of it in total, divided among the 47 homes this screen estimates.
Its plate is compact at 0.81: 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 11.8 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 40-62 Franklin St scores 76 out of 100
Daylight efficiency 90, Interior depth 61, Scale 31, Finance 100 — each out of 100, then weighted.
Score components for 40-62 Franklin St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency85% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 90 | 45% | 40.6 |
| Interior depthdeepest interior point 55 ft from a facade, scored from 80 ft down to 40 ft | 61 | 25% | 15.4 |
| Scale47 estimated homes, scored from 0 up to 150 | 31 | 15% | 4.7 |
| Financecompleted value covers conversion cost with 26% 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 31 out of 100: 47 estimated homes, scored from 0 up to 150.
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 85% daylight figure above deserves.
What the conversion would cost
$360 per square foot all-in across 51,840 sq ft of converted floor, or $18.7M in total — about $397K for each of the 47 homes.
All-in cost per square foot for 40-62 Franklin St: 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 7,707 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 47 homes is $20.8M.
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 $18.7M of work with $2.1M to spare. Value per home would have to fall to $397K — 10% below the assumption — before the conversion stopped penciling, or all-in cost would have to rise from $360 to $400 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 40-62 Franklin St:
Single-assumption flip points for 40-62 Franklin St, each holding the other three at their defaults.
| Circulation efficiencythe binding constraint — the least this building would need | 19% downto 65% |
|---|---|
| Completed value per home | 24% downto $337K |
| Average unit size | 24% upto 929 sq ft |
| Conversion cost per square foot | 36% upto $355/sq ft |
All four are sliders in the survey, where 40-62 Franklin St re-scores against your own numbers.
How it compares in Downtown Boston
40-62 Franklin St ranks 69th of the 96 buildings screened here, against a median score of 89.
Its floor plate is better lit than 44% of them, and shallower than 32% of them at its deepest interior point. On size it is the 88th 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
36th of 52 zoned SKY — the comparison that shares its rules, rents and streets.
52 of the screened buildings are zoned SKY. 40-62 Franklin St ranks 36th 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 55 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: 60-70 Temple Pl
The screened building closest to 40-62 Franklin St in converted floor area is 60-70 Temple Pl: 50,005 sq ft over 7 stories, against 51,840 sq ft over 5 here.
40-62 Franklin St scores 76 to its 89, and with the size held roughly equal most of that shortfall comes from interior depth: 61 out of 100 here, 95 there (deepest interior point 42 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 800 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 40-62 Franklin St $2.8M, 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 40-62 Franklin St
The 4 closest the screen also covers, from 100 ft away. They are the colored outlines on the plan at the top of this page.
- 64-74 Franklin St10 stories · 91% daylit · 94 estimated homes · scores 90/100 (Strong candidate)about 100 ft away
- 33 Arch St34 stories · 72% daylit · 620 estimated homes · scores 71/100 (Strong candidate)about 140 ft away
- 181-185 Devonshire St10 stories · 100% daylit · 68 estimated homes · scores 92/100 (Strong candidate)about 260 ft away
- 77 Franklin St11 stories · 100% daylit · 77 estimated homes · scores 93/100 (Strong candidate)about 260 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.