Planning Board endorses City Council petition to limit AHO height increases in Residence C‑1 districts

The Cambridge Planning Board voted April 15 to transmit a favorable recommendation to the City Council on a petition that would amend the Affordable Housing Overlay (AHO) to prevent developers from using the AHO's open‑space preservation provision to add three extra stories in Residence C‑1 districts except where those lots sit within designated AHO corridors or AHO squares.

The petition: what it changes Evan Spetrini, senior manager for zoning and development in the Community Development Department, told the board the petition stems from a city council policy order asking staff to draft an amendment that would make the AHO open‑space height bonus inapplicable in Residence C‑1 districts. The provision at issue (11.207.5.2.1(e), as described in the staff presentation) allows an AHO project to exceed its otherwise allowable height by up to three stories when certain conditions are met, including preserving at least 5% of the lot as pre‑existing green open space and meeting other gross floor area limits.

Under the multifamily zoning changes adopted earlier this year, base residential height limits increased in many areas and the AHO already includes higher maximums on AHO corridors (12 stories) and AHO squares (15 stories). The petition does not change those corridor or square height ceilings; it would only prevent the additional three‑story open‑space bonus from being used in pure Residence C‑1 districts unless the lot is also in a corridor or square.

Why the petition was filed Spetrini summarized the background: the open‑space bonus was adopted in an earlier AHO amendment; city councilors later expressed concern that, as written, the bonus could allow project heights in some residential districts to exceed the 9‑story cap many councilors had described as a policy goal when the multifamily package was negotiated. The petition narrows the application of the open‑space bonus in response to that concern.

Public comment and board discussion Several members of the public and neighborhood representatives spoke during the public comment period, urging caution on height and shading. Heather Hoffman said: "At what point are we going to put every part of this city in shadow almost all the time?" Several commenters also raised concerns about solar access, tree loss and livability as the city increases allowable building heights in places that remain residential in character.

Board action After questions and a short discussion about intent and the interplay between corridor/square height regimes and the R‑C1 districts, Tom Sinevich moved that the board send a positive recommendation to the City Council; Theodore (Ted) Cohen seconded. On roll call the six full members present voted in favor (Mary Liedecker, Diego Macias, Tom Sinevich, Ashley Tan, Theo Cohen, Mary Flynn). The board's report will accompany the petition to the City Council.

Ending CDD staff said the proposed amendment is narrowly focused; it does not change the definitions of AHO corridors or squares or alter the higher heights already authorized in those designations. The petition will next be considered by the City Council and relevant ordinance committees.