518-540 Atlantic Ave
518-540 Atlantic Ave is a 35-story building in Downtown Boston with 66% of its floor area within daylight reach of a facade. This screen estimates 1,214 homes and scores it 52 out of 100 for office-to-residential conversion suitability.
MA-7 & MA-8 · Screened 2026-10-04 · Worth a feasibility study
Also addressed as 530 Atlantic Ave, 278-294 Congress St and 290 Congress St: Boston’s address records place all 4 on this one footprint.
Where 518-540 Atlantic Ave is
Its block in Downtown Boston, drawn from Boston's own building outlines and street centerlines.
- Already housing
- Not screened
- 518-540 Atlantic Ave
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Across its 34 residential floors this building carries 589,511 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment.
Part of this building is already homes. Boston's assessing records class 2 records here as residential, without a unit count, alongside 3 non-residential records. The figures here treat the whole building as convertible, so read them as an upper bound and check which floors are already housing.
Read with caution. This footprint carries 4 street addresses across 47,678 sq ft, which usually means the city’s GIS has merged a block or complex into a single polygon rather than describing one convertible building.
Modeled conversion metrics for 518-540 Atlantic Ave, 2026-10-04.
| Suitability scoreWorth a feasibility study | 52 / 100 |
|---|---|
| Storiesfrom 418 ft aerial-survey height ÷ 12 ft floor-to-floor | 35 |
| Height bandsfloor plate by floor range, from the city's roof outlines | Floors 1–8: 62,911 sq ft · Floors 9–35: 47,678 sq ft |
| Floor platetypical floor, from the city outlines | 47,678 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 66% |
| Deepest interior pointviability threshold is 80 ft | 78 ft |
| Windowless coretypical floor; the building-wide total is in the text above | 16,501 sq ft |
| Estimated homesat 750 sq ft average | 1,214 |
| Conversion cost$360/sq ft all-in on 1,727,676 sq ft | $622.0M |
| Gap before grantshortfall against completed value | $86.0M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltBoston's own record of the construction year | 2011 |
| ZoningDowntown Boston | M-4 |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
33 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 1,118 ft of exterior wall, and across 34 residential floors the building carries 40,332 ft of it in total, divided among the 1,214 homes this screen estimates.
Its plate is moderately compact at 0.48: 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 35.7 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 518-540 Atlantic Ave scores 52 out of 100
Daylight efficiency 52, Interior depth 5, Scale 100, Finance 80 — each out of 100, then weighted.
Score components for 518-540 Atlantic Ave. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency66% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 52 | 45% | 23.3 |
| Interior depthdeepest interior point 78 ft from a facade, scored from 80 ft down to 40 ft | 5 | 25% | 1.4 |
| Scale1214 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 12% of conversion cost, scored from 60% down to 0% | 80 | 15% | 11.9 |
Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 5 out of 100: deepest interior point 78 ft from a facade, scored from 80 ft down to 40 ft.
Built in 2011
Boston records this building as going up in 2011, 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 66% daylight figure above deserves.
What the conversion would cost
$360 per square foot all-in across 1,727,676 sq ft of converted floor, or $622.0M in total — about $512K for each of the 1,214 homes.
All-in cost per square foot for 518-540 Atlantic Ave: 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 589,511 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 1,214 homes is $536.0M.
What would have to be true
A $86.0M gap before any grant, $76.0M after the modeled one. The smallest single change that would close it: average unit size 12% down.
The shortfall before any grant is $86.0M. Closing it from the value side means each of the 1,214 homes finishing at $512K rather than the $442K the model assumes — 16% more. Closing it from the cost side means getting all-in cost down from $360 to $310 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $504K a home. That is still above the $442K assumed, leaving $76.0M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 518-540 Atlantic Ave, one alone would close the gap at:
Single-assumption flip points for 518-540 Atlantic Ave, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 12% downto 656 sq ft |
|---|---|
| Completed value per home | 14% upto $504K |
| Circulation efficiency | 14% upto 91% |
| Conversion cost per square foot | 17% downto $216/sq ft |
All four are sliders in the survey, where 518-540 Atlantic Ave re-scores against your own numbers.
How it compares in Downtown Boston
518-540 Atlantic Ave ranks 89th of the 96 buildings screened here, against a median score of 89.
Its floor plate is better lit than 8% of them, and shallower than 8% of them at its deepest interior point. On size it is the 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.
Its nearest match in size: 100 Federal St
The screened building closest to 518-540 Atlantic Ave in converted floor area is 100 Federal St: 1,770,665 sq ft over 50 stories, against 1,727,676 sq ft over 35 here.
518-540 Atlantic Ave scores 52 and 100 Federal St only 35, and the difference is a hard fail rather than a matter of degree: the lower one is capped at 35 because its deepest interior point is 92 ft from a facade, past the 80 ft threshold beyond which conversion requires carving a light well. On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 1,100 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 518-540 Atlantic Ave $10.0M, 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 518-540 Atlantic Ave
The 4 closest the screen also covers, from 350 ft away. They are the colored outlines on the plan at the top of this page.
- 600 Atlantic Ave50 stories · 76% daylit · 1,009 estimated homes · scores 83/100 (Strong candidate)about 350 ft away
- 466-472 Atlantic Ave15 stories · 77% daylit · 308 estimated homes · scores 80/100 (Strong candidate)about 460 ft away
- 218-230 Congress St12 stories · 82% daylit · 202 estimated homes · scores 85/100 (Strong candidate)about 590 ft away
- 99 High St34 stories · 70% daylit · 593 estimated homes · scores 61/100 (Worth a feasibility study)about 630 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.