Office-to-Housing Conversion in Downtown Boston

Of 96 office-linked buildings at least 60 feet tall in Downtown Boston, 72 pencil for residential conversion with no subsidy, and 8 more — 4,191 homes — pencil only with a grant from the RESIDE Act.

MA-7 & MA-8 · Downtown Boston, Massachusetts · Screened from City of Boston open GIS data · Last updated 2026-10-04 · Cite or download the data

Buildings screened

≥ 60 ft, office use on the assessing roll

Pencil unsubsidized

no grant required

Unlocked by RESIDE

pencil only with the grant

Homes unlocked

4,191

in those buildings

Never pencil

at default assumptions

Grant requested

$79.7M

under the modeled formula

Loading building data…

Every assumption in the model is a slider. Change conversion cost, unit size, circulation efficiency or completed value in the Assumptions tab and all 96 buildings re-score and re-rank live. Every building also has a page of its own: see all 102 by address. The full analysis continues below.

72 pencil without a grant, and a RESIDE grant unlocks 8 more

Downtown Boston has the oldest office stock of the cities in this survey that record construction years, and the highest completed value per home of the four. On this model, the market wins.

89 of the 96 buildings screened here score at least 50, meaning the model rates them worth a professional feasibility study. The median building has 90% of its floor area within daylight reach and a deepest interior point 49 feet from a window, and 7 are past the 80-foot threshold where conversion needs a carved light well.

Of 96 office-linked buildings at least 60 feet tall, 72 pencil for conversion unsubsidized and 8 are unlocked by a modeled RESIDE grant. Across the 17 that score at least 50 and do not already pencil, the median financing gap is $21K per home. The grant’s per-home cap of $60K is not what limits it here: 16 of those 17 buildings reach the $10.0M cap on a single award first, and at that size a modeled grant unlocks 8 of them.

That answer rests on one number more than any other. This model values a converted apartment at $442K, the average price per apartment unit sold in the Boston market in the twelve months through April 2026, the highest of the four cities. An average across the whole market includes new luxury buildings, and a converted 1920s office floor is not one, so treat the count that pencils as an upper bound and use the completed-value slider below to test it.

Floor counts here are a building’s height divided by 12 feet, because Boston’s assessing roll records no storey count for commercial buildings. 39 buildings that cleared the height screen are absent because the city’s outlines carry no height for too much of their roof, and this survey withholds them rather than modeling a tower from part of its roof.

Why most office buildings can never become apartments

The binding constraint on office-to-residential conversion is floor-plate geometry, not financing. Apartments need light and air; office floors were built deep on purpose.

150 Oliver St — 80% of the building’s floor area sits within daylight reach of a facade; the drawing shows its typical floor, where the share is 82%. The shading is daylight, darkest at the windows and gone 35 ft in. The hatched area is windowless core: 5,653 sq ft per typical floor that must be renovated but can never be rented as an apartment. The dimension marks the deepest interior point, 74 ft from the nearest window.

Building codes limit how far a habitable room can sit from a window — roughly 25 to 35 feet. This model erodes each real building footprint inward by 35 feet, the generous end of that range. What survives the erosion is windowless dead core. What remains is the daylit band where apartments can legally go.

Across the 96 buildings screened here, the median has 90% of its floor area within daylight reach and a deepest interior point 49 feet from the nearest window. 7 of them are past the 80-foot threshold where conversion requires carving a light well through the building — at which point it effectively never pencils.

Conversion cost is charged on gross floor area while revenue is earned only on the daylit band. That is not an accounting trick — it is the real economics. You must gut, re-plumb and sprinkler the windowless core, but you can never rent an apartment in it. Deep floor plates are penalized twice, which is precisely why they fail in practice.

This is why a subsidy program alone does not produce conversions, and why a list of vacant buildings is not a pipeline. Information was never the bottleneck — cities have published vacancy reports for years. The bottleneck is that establishing which specific buildings are physically convertible is expensive expert work, and most of them are not.

The 8 buildings a RESIDE grant would unlock, if they qualify

Each of these fails on financing rather than geometry: the floor plate works, the pro-forma does not, and a grant closes the difference. None has been checked against the law’s vacant-and-abandoned test, which public GIS data cannot show. Buildings are ranked by conversion suitability score.

Buildings in Downtown Boston that pencil for residential conversion only with a RESIDE Act grant, modeled 2026-10-04.
Address	Score	Stories	Homes	Daylit	Depth	Gap	Grant
600 Atlantic Ave	83	50	1,009	76%	48 ft	$1.9M	$10.0M
225 Franklin St	80	40	722	75%	50 ft	$7.5M	$10.0M
14 Bowdoin St	74	25	633	75%	60 ft	$7.1M	$10.0M
93-101 Arch St	72	22	389	74%	61 ft	$6.5M	$10.0M
90 Oliver St	70	45	743	76%	68 ft	$1.5M	$10.0M
300 Boylston St	70	13	275	76%	69 ft	$603K	$10.0M
255 State St	68	11	162	74%	68 ft	$2.9M	$9.7M
69-81 Tremont St	64	14	258	72%	72 ft	$6.7M	$10.0M

Also profiled in detail — the highest-scoring buildings in the survey: 36-44 Broad St, 147 Milk St, 315-333 Washington St, 417-435 Washington St, 157-175 Devonshire St, 252-272 Tremont St, 150-152 State St, 14-24 Federal St, 99 Chauncy St, 20 Custom House St, 74-84 State St, 43-45 Devonshire St, 75-101 Federal St, 28-38 Winter St, 155 Federal St, 6-6B Beacon St and 12-14A Beacon St.

“Gap” is conversion cost minus completed value before any subsidy. “Grant” is the modeled RESIDE award. Where the grant exceeds the gap, the formula is over-funding the project — see the finding above. All 96 screened buildings, including those that do not pencil, are in the survey above and in the full list by address, each linked to its own analysis.

What a RESIDE appropriation would buy in Downtown Boston

Congress has not funded the program. If it does, how HUD sizes each award matters as much as the amount.

For each funding level, the table shows the most of the 8 buildings above that the money could close, taking the lowest cost per home first: once with awards at the modeled formula, and once with each award sized to the building’s actual financing gap. Funding all 8 would take $79.7M under the formula and $34.7M sized to the gap.

Most buildings and homes each amount could fund in Downtown Boston, modeled 2026-10-04.
Appropriation	Formula: buildings	Formula: homes	Gap-sized: buildings	Gap-sized: homes
$10.0M	1	1,009	4	2,189
$25.0M	2	1,752	6	3,544
$50.0M	5	3,496	8	4,191
$100.0M	8	4,191	8	4,191

These are upper bounds for one study area, not forecasts. Any appropriation is national and competitive across every eligible state and city, and HUD’s priorities are not modeled. The law’s $1 million minimum award, which applies in a year with at least $100 million, is not applied here. Every building would still have to meet the law’s vacant-and-abandoned test, and homes are valued at market rate although RESIDE housing must be mostly affordable, which would widen every gap.

What Boston is already doing

Boston already pays for conversions. Its Office to Residential Conversion Program, launched in October 2023, offers a 75% property tax abatement for up to 29 years. The city extended it on December 12, 2025: it accepts applications through December 31, 2026, and approved projects must start construction by December 31, 2027. When it was extended, it had received 22 applications to convert 27 buildings into 1,517 homes, 284 of them income-restricted, with 251 under construction or complete.

This model does not include that abatement, so a building it scores as close is one the city’s program may already push over the line. The two work on different costs: the abatement lowers what a finished building costs to own, and a RESIDE grant, if Congress funds the pilot, would lower what it costs to build.

Downtown Boston’s office vacancy rate was 18.7% in the second quarter of 2026, by CBRE’s count, and 96 buildings being screened does not mean 96 buildings are empty.

Downtown Boston spans two congressional districts. Massachusetts's 8th District, represented by Stephen Lynch since 2001, takes in 93 of the 102 buildings on this page's map, homes already included, and the 7th, represented by Ayanna Pressley since 2019, takes in 9. Both won their September 1, 2026 primaries.

What the RESIDE Act, Section 210 of the ROAD to Housing Act, funds

The RESIDE Act is law, but it has no money yet, its grants go to cities rather than developers, and only vacant and abandoned buildings qualify. All three facts are widely misreported.

The Revitalizing Empty Structures Into Desirable Environments Act was introduced as H.R. 5591 in the 119th Congress and enacted as Section 210 of the 21st Century ROAD to Housing Act, which became law without the President’s signature on July 11, 2026. It authorizes HUD to run a pilot program, in fiscal years 2027 through 2031, of competitive grants to convert vacant and abandoned buildings into attainable housing, with priority for economically distressed communities, Opportunity Zones, needs in a city’s consolidated plan, and cities that have passed ordinances easing conversion.

The program has no money yet. The law authorizes it only “subject to the availability of funds appropriated,” and as of September 9, 2026, Congress had appropriated nothing. In a year Congress provides at least $100 million, each grant is $1 million to $10 million; with less, HUD must spread the money across as many grants as it can. The widely quoted $100 million a year from HOME funding above $1.35 billion comes from the introduced bill, not the law.

Most empty offices would not qualify. The law covers only a vacant and abandoned building: one built for commercial or industrial use that code enforcement has found unsafe, with no corrective action 90 days after the owner was notified, or that is in court-ordered receivership or nuisance abatement, or is abandoned under state law. This survey cannot see code enforcement or court records, so a building shown as unlocked by RESIDE here is one that would pencil with a modeled grant if it qualified. The homes must also be attainable, serving households up to 120% of area median income with most units affordable at 60%, while this model values every home at market completed value, so its grant results are optimistic.

Individual awards are capped at $10.0M, and eligible applicants are HOME participating jurisdictions — states and local governments — not private developers or building owners. That changes what this tool is for. It is not a developer’s capital stack; it is a worksheet for the grant application a city would file, and for the question of which buildings would justify the ask.

Because HUD has not published a Notice of Funding Opportunity, the award formula used here — 30% of eligible conversion cost, capped at $60K per home and $10.0M per award — is modeled on how comparable HUD gap-financing programs are structured. The $10.0M per-award cap is statutory. The rest is an assumption, and 47 of the 96 buildings here hit that statutory ceiling.

More on the law: The ROAD to Housing Act explained · Environmental review changes · CDBG and HOME changes · Opportunity Zones · The Innovation Fund · The Build Now Act · Manufactured housing and the chassis rule · How RESIDE grants should be sized · The ban on large investors buying homes

How this was computed, and what it cannot tell you

Every figure on this page is reproducible from public data. Stating the limits is part of the method, not a disclaimer attached to it.

Building outlines and roof heights from the City of Boston’s aerial survey, parcels, addresses and zoning come from the City of Boston’s open data services, and use and year built from the Assessing Department’s FY2026 roll. Footprints are projected to a local tangent plane in feet, eroded inward by 35 feet to separate daylit band from dead core, and the largest circle that fits inside each footprint gives the distance from the deepest interior point to the nearest facade. Unit yield is the daylit band times a 80% circulation factor divided by a 750 sq ft average home, across every floor above the ground floor. Cost is a base of $260/sq ft plus itemized change-of-occupancy triggers — plumbing risers, operable windows, egress stairs, sprinklers — weighed against completed value, then against the modeled grant.

Two further figures appear on each building’s own page. Window line is the building’s exterior wall summed across its residential floors and divided by the homes estimated in it: daylight efficiency says how much of a floor is near glass, and window line says whether there is enough glass to go round, since every bedroom needs one. Plate shape is the isoperimetric quotient — 1.00 for a circle, about 0.79 for a square, lower for anything longer or more articulated. The direction that favours housing is the opposite of the one that favours offices: a compact plan is the cheapest envelope per square foot to build and heat, while apartments are sold by the window, so the notched outline an office would call wasteful is the one that converts.

For Downtown Boston the model replaces 2 defaults with local figures. Completed value per home is $442K: the average price per apartment unit sold in the Boston market in the twelve months through April 2026 (Yardi Matrix, 2026-10-04). The seismic retrofit allowance is $0 per sq ft: Massachusetts' existing-building code requires a seismic upgrade on a change of occupancy only when the building moves to a higher risk category, and office and apartment buildings are both Risk Category II (UpCodes, 2026-10-04).

The geometry math is validated against shapes with known analytic answers, and computed floor areas agree with the city’s own recorded areas to within 0.01%, which confirms the coordinate projection. The browser model that powers the interactive survey above is checked against the Python engine on every build; both must agree on units, cost, grant, gap, tier and score for all 96 buildings.

What this tool does not know

It screens geometry from footprints. It cannot see interior cores, columns, ceiling heights, post-tension slabs or mechanical systems.
It does not know which buildings are vacant. Downtown Boston’s office vacancy rate was 18.7% in the second quarter of 2026; this screen does not assert that any specific building is empty.
Story count is derived from aerial-survey height ÷ floor-to-floor, not read from plans.
It does not model the statute’s four priorities — economically distressed communities, Opportunity Zones, needs in the city’s consolidated plan and local ordinances that ease conversion — or Boston’s own 29-year tax abatement for conversions.
It cannot tell whether a building would qualify for a RESIDE grant, which requires a code-enforcement finding, receivership or abandonment, and it values every home at market rate although RESIDE-funded housing must be mostly affordable.
HUD has not published an award formula, so every per-project grant here is modeled rather than known.
A high score means worth a professional feasibility study — never “convertible.”
Completed value per home is the Boston market’s average sale price per apartment unit, an average that includes new luxury buildings. It is likely high for a converted office floor, and it is the assumption this page’s finding leans on most.
Roof heights date from the city’s 2010–2011 aerial survey, updated since from imagery and LiDAR. A building altered since without an update would be measured at its old height; floors are its height divided by 12 feet, because the assessing roll records no commercial storey count.
Buildings are assembled from roof pieces by the parcel under them and by contact, and rejoined where one roof was cut at a parcel line, because the city’s outlines carry no building id. Use, year built and housing records are read per parcel, so buildings sharing a parcel share them. Where those shared records would make a building housing, they cannot say which building on the parcel holds the homes: 3 buildings are marked “Excluded: residential records on a shared parcel; building use unverified” and left out of every count on this page without being called housing.
39 buildings are withheld because pieces of their roof carry no recorded height, not because they failed the screen.
Party walls are treated as facade. The geometry model treats every outline edge as exposed, so Downtown’s attached stock looks more favourable than it is.

Questions

Can empty office buildings in Downtown Boston be converted into housing?

Of 96 office-linked buildings at least 60 feet tall in Downtown Boston, this model rates 89 at least worth a professional feasibility study. At default assumptions 72 pencil without a subsidy and a modeled RESIDE Act grant unlocks 8 more. That rests on valuing a converted home at $442K, the Boston market's average sale price per apartment unit, which is likely high for converted older offices, so the count that pencils is an upper bound.

Why do most office-to-residential conversions fail?

Floor-plate geometry, not financing. Apartments need light and air, and building codes limit how far a habitable room can sit from a window — roughly 25 to 35 feet. Office floors were built deep on purpose, so the middle of the plate is windowless core that can never legally become a bedroom. In this survey the median building has 90% of its floor area within daylight reach and a deepest interior point 49 feet from the nearest window. 7 of the 96 buildings are past the 80-foot threshold where conversion requires carving a light well, at which point it effectively never pencils. No subsidy fixes bad geometry.

What is Boston's Office to Residential Conversion Program?

A City of Boston incentive that offers a 75% property tax abatement for up to 29 years to office buildings converted to housing. It launched in October 2023 and was extended on December 12, 2025; it accepts applications through December 31, 2026, and approved projects must begin construction by December 31, 2027. It had received 22 applications to convert 27 buildings into 1,517 homes. This page's model does not include the abatement.

Why does this page screen fewer buildings than there are office towers downtown?

It screens office-linked buildings at least 60 feet tall inside the Planning Department's Downtown neighborhood: the Financial District, Downtown Crossing and Government Center. Back Bay and the Seaport are outside it. It also withholds 39 buildings whose outlines carry no height for too much of their roof, rather than modeling a tower from part of its roof. A building counts as office-linked when a record on its parcel carries an office land-use code on the FY2026 assessing roll.

What is the RESIDE Act and is it law?

Yes, it is law. The RESIDE Act — Revitalizing Empty Structures Into Desirable Environments — was introduced as H.R. 5591 and enacted as Section 210 of the 21st Century ROAD to Housing Act (Public Law 119-101), which became law without the President's signature on July 11, 2026. It authorizes HUD to run a pilot program, in fiscal years 2027 through 2031, of competitive grants to states and local governments to convert vacant and abandoned commercial and industrial buildings into attainable housing.

Which buildings qualify for a RESIDE Act grant?

Far fewer than "empty offices" suggests. The law covers only a vacant and abandoned building: one built as a warehouse, factory, mall, strip mall or hotel, or for another commercial or industrial use such as offices, that code enforcement has found unsafe, with no corrective action 90 days after the owner was notified, or that is in court-ordered receivership or nuisance abatement, or is abandoned under state law. A building that is merely empty does not qualify. The homes it creates must be attainable housing, serving households earning up to 120% of area median income, with most units affordable at 60%.

What does the ROAD to Housing Act mean for office conversions in Downtown Boston?

Several parts of the 21st Century ROAD to Housing Act apply. The RESIDE Act (Section 210) would fund conversions of vacant and abandoned buildings, if Congress appropriates money and a building meets that test. Section 206 gives HUD-funded conversions of existing office buildings a lighter environmental review once HUD writes its rules. Section 204 lets a city spend up to 20% of its Community Development Block Grant on new affordable housing construction. Section 201 lets HUD favor housing grants in Opportunity Zones, but none of the 96 buildings screened here sits in a 2018 Opportunity Zone tract.

How much money does the RESIDE Act actually provide?

None yet. The law authorizes the pilot only "subject to the availability of funds appropriated," authorizes no new funding, and as of September 9, 2026, Congress had appropriated nothing for it. In a year Congress provides at least $100 million, each grant is between $1 million and $10 million; with less, HUD must spread the money across as many grants as it can. The often quoted $100 million a year from HOME funding above $1.35 billion comes from the introduced bill and is not in the law.

Who applies for a RESIDE Act grant — the developer or the city?

The city. Eligible applicants are HOME participating jurisdictions — states and local governments — not private developers or building owners. That makes this tool a municipal grant-application worksheet rather than a developer's pro-forma: it estimates what Boston could credibly ask HUD for, and which buildings would justify the ask.

Does this tool know which Boston buildings are actually vacant?

No. Downtown Boston's office vacancy rate was 18.7% in the second quarter of 2026, but this screen does not assert that any specific building is empty. Ownership, lease status and tenancy are outside what public outline, zoning and assessment data can show, and the RESIDE Act's vacant-and-abandoned test is a legal finding, not a data lookup.

How accurate is this analysis?

It is a screen, not a feasibility study. The geometry is computed from real city footprints and aerial-survey heights, and the floor-plate math is validated against shapes with known analytic answers; computed floor areas agree with the city's own recorded areas to within 0.01%. But the model cannot see interior columns, existing cores, ceiling heights, post-tension slabs, or mechanical systems, and story counts are inferred from height rather than read from plans. A high score means a building is worth a professional feasibility study — never that it is convertible.

Cite or reuse this analysis

Everything on this page is free to quote, republish and build on, with credit. The scored dataset behind it is one download.

Suggested citation

RESIDE Act Feasibility Engine, “Office-to-Housing Conversion in Downtown Boston,” resideact.org/boston, updated 2026-10-04.

Download the scored dataset (GeoJSON)Read the method

The text and dataset are licensed under CC BY 4.0: copy, adapt and republish them, commercially or not, with credit and a link back. Footprints, heights and zoning come from the City of Boston, whose own terms still apply to that source data. See the terms of use.

Sources

Boston's Office to Residential Conversion Program offers a 75% property tax abatement for up to 29 years. Extended on December 12, 2025, it accepts applications through December 31, 2026, and approved projects must start construction by December 31, 2027. It had received 22 applications to convert 27 buildings into 1,517 homes, 284 of them income-restricted, with 251 under construction or complete. City of Boston, “Office to Residential Conversion Program Extended as it Surpasses 1,500 New Homes” — verified 2026-10-04.
Downtown Boston's office vacancy rate was 18.7% in the second quarter of 2026, down from 19.1% a year earlier. CBRE, “Downtown Boston Office Figures Q2 2026” — verified 2026-10-04.
The average price per apartment unit sold in the Boston market in the twelve months through April 2026 was $441,514, up 14%. Yardi Matrix, “Boston Multifamily Market Report” — verified 2026-10-04.
The RESIDE Act is Section 210 of the 21st Century ROAD to Housing Act (Public Law 119-101), which became law without the President's signature on July 11, 2026. Section 210 authorizes a HUD pilot program, in fiscal years 2027 through 2031 and subject to appropriations, of competitive grants to HOME participating jurisdictions to convert vacant and abandoned buildings into attainable housing; in a year at least $100M is available, each grant is $1M to $10M. U.S. Government Publishing Office, “Public Law 119-101, 21st Century ROAD to Housing Act” — verified 2026-09-14.
As of September 9, 2026, HUD had issued no Notice of Funding Opportunity, guidance or rule for the RESIDE pilot, and no funds had been appropriated for it. Bipartisan Policy Center, “21st Century ROAD to Housing Act Implementation Tracker” — verified 2026-09-14.
The RESIDE Act was introduced as H.R. 5591 in the 119th Congress. As introduced, it would have funded the program with up to $100M a year of HOME appropriations above $1.35B; the enacted law does not. Congress.gov, “H.R.5591 — RESIDE Act” — verified 2026-09-14.
Of the 102 buildings on the Downtown Boston map, homes already included, 93 lie in Massachusetts's 8th Congressional District and 9 in the 7th, checked building by building against the 120th Congress district boundaries. U.S. Census Bureau, “TIGERweb Legislative Map Service: 120th Congressional Districts” — verified 2026-10-04.
In Massachusetts's September 1, 2026 primaries, Stephen Lynch won the Democratic nomination in the 8th District over Patrick Roath, and Ayanna Pressley was unopposed in the 7th. The Washington Post, “Massachusetts House primary results: Stephen Lynch defeats Patrick Roath” — verified 2026-10-04.
Building outlines with roof heights, parcels, addresses, street segments, neighborhood boundaries and zoning come from the City of Boston's open data services, and land use and year built from the Assessing Department's FY2026 property assessment. City of Boston, “Analyze Boston: Buildings with Roof Breaks, Parcels 2025, SAM, Neighborhood Boundaries, Zoning Subdistricts, Property Assessment FY2026” — verified 2026-10-04.
Completed value per home is $442K: the average price per apartment unit sold in the Boston market in the twelve months through April 2026. Yardi Matrix, “Boston Multifamily Market Report” — verified 2026-10-04.
The seismic retrofit allowance is $0 per sq ft: Massachusetts' existing-building code requires a seismic upgrade on a change of occupancy only when the building moves to a higher risk category, and office and apartment buildings are both Risk Category II. UpCodes, “Massachusetts Existing Building Code 2021, Chapter 10, Section 1006.3” — verified 2026-10-04.

The scored dataset behind this page is available as GeoJSON. Findings generated 2026-10-04 from City of Boston open data (Buildings with Roof Breaks, Parcels 2025, SAM Addresses and Street Segments, Neighborhood Boundaries, Zoning Subdistricts; FY2026 Property Assessment).