A Cambridge City Council panel’s proposal would legalize six-story buildings. Everywhere.

A Cambridge City Council panel’s proposal would legalize six-story buildings. Everywhere.

A Cambridge City Council panel’s proposal would legalize six-story buildings. Everywhere.

By Andrew Brinker

Picture the best of what Paris has to offer, a vibrant street life in densely packed neighborhoods. One of the secrets to the city’s charm is the size of most of those graceful buildings: six stories.

That idea — dense, six-story housing in abundance — is the inspiration behind a proposal from two Cambridge city councilors that amounts to something of a moonshot on the biggest challenge facing Boston’s neighbor to the north: the acute shortage of housing.

Councilors Burhan Azeem and Sumbul Siddiqui want to legalize six-story apartment buildings by-right citywide, meaning any housing development up to that height that fits other zoning parameters would not need city zoning approval.

In effect, the proposal would essentially scrap the city’s current neighborhood-by-neighborhood zoning scheme for anything six stories or smaller. From tight-packed East Cambridge to leafy Strawberry Hill, six-story buildings could rise largely unencumbered.

It would also, at least symbolically, make Cambridge the first city in the state to end single-family zoning as the default for housing construction. That does not mean single-family homes wouldn’t be allowed anymore, but rather that something larger than a single-family house could be built on any residential lot in the city.

The proposal comes as cities and towns across Eastern Massachusetts are engaged in heated fights over solving a housing shortage that has become the state’s most intractable issue. But most of those debates, taking place in communities with shrinking populations and skyrocketing prices, have been about comparatively modest reforms. Should this zoning overhaul come to fruition in Cambridge, it would represent far and away the most ambitious attempt at a solution here, and one of the most sweeping zoning reform efforts anywhere in the United States.

“If we want to take the housing crisis seriously, we need to be doing a lot better than we are right now,” said Azeem. “Our goal is to take a big shot at making our zoning much better than it currently is, in a way that is going to promote affordability and density and more housing.”

Why six stories? It’s a residential building sweet spot — and the reason new apartment buildings all over Greater Boston are often five or six stories tall. Generally speaking, the shorter or smaller a building, the more difficult it is to finance, because there are fewer apartments to bring in revenue. Go taller than six stories, and different building requirements kick in that dramatically increase the per unit cost of development.

They argue that the scale of the proposal meets the scale of the problem. By some measures, Cambridge has the worst localized housing crisis in Massachusetts and some of the highest housing costs in the United States. The median rent for a one-bedroom apartment is $2,645 a month, according to rental website Apartment List. It is also one of the most densely populated cities in the country — in Massachusetts only its twin city of Somerville packs more people per square mile than Cambridge — meaning there’s little room to build new housing in any direction but up.

Azeem proposed the zoning change last week during a meeting of the City Council’s housing committee, which voted unanimously to draft language for the proposal. It will still have to go through several public hearings and be approved by the housing committee and then the full council before becoming law. So it’s early yet.

And the proposal is sure to be controversial.

As in many communities, housing has become a top political issue in Cambridge, with several bruising policy battles that have left behind simmering tensions. Some on the left say that enabling larger buildings would only create expensive housing that is beyond the reach of everyday people. Meanwhile politically influential homeowner and neighborhood groups have frequently opposed zoning for taller buildings out of worry their neighborhoods would change.

Last Friday, the Cambridge Citizens Coalition, a resident group that has frequently opposed upzoning proposals, published its opposition to the proposal. Allowing six-stories everywhere, the group said, would only further drive up the price of housing because it would incentivize market-rate construction, while encouraging developers to replace yards and other green space with brick and concrete. And, they said, Cambridge’s original zoning was never grounded in racism, so there is no history of exclusionary zoning to undo.

“We will see very little affordable housing from this proposal, just more very expensive units for the very wealthy, including increasing numbers of McMansions,” the group wrote.

Instead, the group said, Cambridge should focus on fitting new units into existing buildings, not constructing new ones.

But Siddiqui counters that the six-story proposal would create more affordable housing because of the city’s inclusionary zoning ordinance. That rule requires 20 percent of the units in new market-rate buildings be reserved for affordable housing and has been the top creator of subsidized housing in the city in recent years.

“Our most successful affordable housing policy historically has been inclusionary zoning,” Siddiqui said. “But we know solving the housing crisis is about using as many policies as we have at our disposal. When you allow more density, you’re allowing our inclusionary zoning to generate more affordable housing.”

And to the neighborhood groups that have historically opposed higher buildings, Azeem said that Cambridge already has many, and that the proposal would not change the city that dramatically.

Cambridge has become something of a laboratory for housing reform. First it passed a landmark policy that allows affordable housing projects to skirt traditional zoning rules. Last year, the council, prodded by Azeem, boosted that policy by allowing affordable developments to be as high as 15 stories without needing permission from the local zoning board.

The council also passed a policy, likewise pushed by Azeem, that eliminated minimum parking requirements at new buildings, which dictated how many parking spots must accompany residential units. Parking, he and other Cambridge housing advocates argued, dramatically increases the cost of building.

Azeem and Siddiqui’s proposal has echoes in other cities that have “ended” single-family zoning — Portland, Ore., for example — by allowing taller and denser buildings citywide.

But even Portland only allows up to six units on most residential lots. Six stories citywide would be among the most ambitious efforts anywhere.

“This will be game changing if it passes,” said Azeem. “We would actually see what we can achieve when the prohousing movement wins.”