BOSTON’S AFFORDABLE HOUSING CRISIS is usually framed as a shortage—of land, of money, or of political will. In reality, it is more accurate to describe it as a cost-structure and governance failure.

The city already owns the land where new housing could be built. Proven construction methods already exist to build housing at much lower cost than standard methods. What is missing is a strategy that aligns these elements into a system that actually produces entry-level homeownership.

A proposal developed by Greater Grove Hall Main Streets, in partnership with the Boston-based architectural firm Payette, offers such a strategy. Known as Urban Starter Homes, the proposal demonstrates how publicly owned “sliver lots” can be used to deliver affordable, ownership-oriented housing at neighborhood scale—using triple-deckers as the model, modular construction, and land-use policies that directly address the real barriers to affordability.

While Boston provides the primary case study, the conditions this proposal responds to—publicly owned vacant land, high construction costs, shrinking paths to ownership, and limited housing subsidy dollars—exist in cities and towns across Massachusetts and across the country.

Boston owns more than 1,200 vacant or underutilized parcels, including at least 158 “sliver lots”—small parcels typically between 1,000 and 3,000 square feet—that the city itself has identified as suitable for infill housing. These parcels are scattered across various Boston neighborhoods, but are concentrated in Roxbury and Dorchester.

Individually, these lots are often dismissed as too small or irregular to attract private development. Collectively, they represent a significant public asset that has largely been excluded from the city’s housing strategy.

While Boston has identified 158 sliver lots suitable for small-scale infill—suggesting a near-term opportunity of perhaps 450–500 units under a three-unit urban starter home model—the broader opportunity is significantly larger. The city’s land audit has identified approximately 530 parcels suitable for infill housing. That could translate to 1,500 to 1,600 units under this model in an ideal, scaled implementation.

Many municipalities across Massachusetts hold similar inventories of small, irregular parcels acquired through tax foreclosure, infrastructure projects, or decades-old planning decisions. Most remain idle—not because they lack potential, but because no scalable policy framework exists to use them productively.

The Urban Starter Homes proposal treats these parcels not as leftovers, but as the foundation of a replicable model housing system.

In neighborhoods like Roxbury, the proposal documents a typical infill parcel size of approximately 3,600 square feet, with average land costs of roughly $60 per square foot—placing the land value alone at approximately $216,000 per lot before construction begins.

That land cost is embedded in nearly every new housing unit in Boston, whether market-rate or deed-restricted “affordable” housing. The starter home proposal removes that cost entirely from the purchase price by separating land ownership from homeownership.

Under this model, the city retains ownership of the land and issues a long-term ground lease, while residents own the housing structure itself. Buyers are homeowners—with mortgages, equity, and stability—but they are not financing speculative land value.

Rather than introducing an unfamiliar housing form, the proposal is based on the construction of three-unit triple-deckers—one of the most historically common and successful forms of what planners call “missing middle housing” in Massachusetts cities.

Missing middle housing refers to small, multi-unit buildings—typically two to four units—that fall between single-family homes and large apartment complexes. These housing types, including duplexes, triple-deckers, and small multifamily buildings, were once common across Boston neighborhoods but are now rarely built due to zoning, financing, and construction cost barriers.

Each sliver lot supports a three-unit building, typically configured as a stacked triple-decker that aligns with existing streetscapes in many Boston neighborhoods.

Within that structure, the ownership model can vary depending on policy goals. Most commonly, units would be structured as condominiums, allowing each household to own an individual unit while sharing common elements such as the roof and exterior. In some cases—particularly on larger or assembled parcels—the model could be adapted into townhouse-style configurations, where units are side-by-side rather than stacked.

By making use of increasingly high-quality modular housing components, the proposal directly confronts one of the largest drivers of unaffordability: construction costs.

Traditional site-built housing costs approximately $166 per square foot, according to 2023 data. Manufactured or modular housing that year cost about $87 per square foot—or nearly 50 percent less. The savings come from off-site fabrication, not from reduced standards. Structural systems, kitchens, bathrooms, stairs, bedrooms, and living spaces are all built to code.

While the structural modules are standardized for efficiency, interior layouts are intentionally flexible. In several unit designs, a room that could function as a bedroom can also serve as a home office or be adapted for licensed in-home childcare.

This flexibility has direct policy implications. For residents, for example, in-home childcare can provide supplemental income, strengthening household financial stability and supporting mortgage sustainability. For the city, it would help address a chronic shortage of affordable childcare without requiring new standalone facilities.

Leveraging the combined impact of city-owned lots, land-use policy in which the city retains ownership of the parcel, and modular housing construction methods, a typical housing unit produced under the Urban Starter Homes model could be priced at approximately $100,000, with a down payment of $14,400 and an estimated monthly mortgage in the range of $400 to $550, depending on financing assumptions.

In Boston, that is not just affordable—it is hard to fathom. It’s the rent for a very modest apartment a generation ago, not the monthly cost of homeownership in 2026 in one of the most expensive housing markets in the country.

This price point puts homeownership within reach of households earning $40,000 to $70,000 annually, depending on financing terms. When housing costs fall to that level, families are no longer just getting by—they have room to save, to invest, to build stability. In a city where the Boston Fed found a decade ago that the median net worth of Black households was just $8, creating a realistic path to ownership at this price point is not just a housing strategy—it is powerful wealth-building strategy.

In comparison to this achievable price point of $100,000 per unit, deed-restricted affordable ownership units in Boston typically range from $250,000 to $400,000, while market-rate homes often exceed $750,000.

One of the most consequential features of the Urban Starter Homes proposal is what it does not require.

Because affordability is achieved through public land leasing, lower construction costs, and efficient density, the model does not rely on deep housing subsidies to make units affordable. In many cases, little or no direct subsidy is required to reach entry-level price points.

This does not eliminate the need for housing subsidies overall. Rather, it allows them to be used more strategically. Traditional affordable housing production often depends on stacking multiple subsidies to offset high land and construction costs. Those funds are finite. Each subsidized unit consumes a large share of available housing dollars, limiting total production.

By reducing or eliminating the per-unit subsidy requirement, this model allows scarce housing dollars to go further—supporting more units, deeper affordability where needed, preservation of existing housing, or households with the greatest challenges.

Vacant city-owned parcels are not neutral assets. They impose ongoing maintenance costs, generate complaints, create public-safety concerns, and expose municipalities to legal liability. The Urban Starter Homes proposal converts those liabilities into productive, revenue-generating assets.

What has to happen for the Urban Starter Home model to get started?

The City of Boston needs to reclassify sliver parcels into the housing pipeline rather than making them available for abutters to purchase. It then needs to establish a standard ground lease structure to retain city-ownership of the land, bundle several sites into a pilot project, and issue a request for proposals to developers to test pricing and the ability to deliver on the model.

For decades, affordable housing has depended on layers of subsidies to make the numbers pencil out. This approach lowers the cost structure itself.

It is far closer than traditional affordable housing models to a market-based solution—one where the public sector sets the conditions by retaining land, and the private market does what it does best: builds, finances, and delivers housing at scale. That balance should appeal across the political spectrum, especially to those wary of simply spending more public dollars without changing the underlying economics.

The housing crisis in Boston – and across the Commonwealth – will not be solved by any single approach. But models like Urban Starter Homes demonstrate how cities can expand access to homeownership in ways that are scalable, cost-effective, and less dependent on scarce subsidy dollars—by directly addressing the key cost drivers of land, construction, and scale.

Ed Gaskin is executive director of Greater Grove Hall Main Streets.

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