Green Building/Zoning Task Force

City Hall Annex Plaque

The City Manager appointed the Green Building/Zoning Task Force in April 2008 to work with City staff to analyze various approaches and to encourage energy efficient building practices. Key issues that the group looked at included adopting green building requirements such as LEED criteria for large scale developments, approach to green roofs, solar access, and identifying and addressing any impediments to building green in the zoning ordinance.

Appointees to the task force represented diverse perspectives and included architects, residential owners, developers, solar installers, and representatives of advocacy groups, local universities, and the Cambridge Planning Board. City staff from Public Works, Inspectional Services, Historical Commission, and Community Development participated in this effort.  The Task Force  meet  monthly for eight months and developed recommendations for submission to the City Manager.

Green Building/Zoning Task Force Recommendations

On August 2, 2010, the City Council adopted a green building zoning amendment based on the Green Building/Zoning Task Force Recommendations. The amendment includes the following key elements.

Green Building Standards for Large Development/LEED

All major new construction and significant rehab of existing buildings already subject to special permit or development consultation would be required, at a minimum, to meet Leadership in Energy and Environmental Design (LEED) green building criteria at the following levels:

  • 25,000 to 49,999 sq. ft. to meet LEED ‘Certified’ level
  • 50,000 sq. ft. and larger to meet LEED ‘Silver’ level

Formal certification from US Green Building Council (USGBC)/ Green Building Certification Institute (GBCI) would not be required.

Green Roofs

Green roofs would be excluded from the calculation of gross floor area (GFA) even when access to the rooftop is provided. Currently, access to a rooftop, when located above the third floor, triggers the roof area being included in the GFA calculation.

As an incentive to create green roofs, decks or patios less than or equal to 15% of the green roof area and set back 10’ from all building edges may also be excluded from the calculation of GFA. This would be permitted as of right in non residential districts and high density residential districts (Residence C-1A, C-2, C-2A, C-2B, C-3, C-3A, and C-3B). A special permit would be required in the remaining residential districts.

Impediments to Building Green in the Zoning Ordinance

Certain green elements that may reduce a building’s energy consumption and improve indoor environmental quality would be excluded from the calculation of GFA. These include:

  • double skin facade exterior walls
  • extensive exterior wall insulation
  • shading devices such as overhangs, eaves, awnings, pergolas, and arbors

Solar Energy Systems

Building mounted solar energy systems would be defined as mechanical equipment in the zoning ordinance and hence would not be subject to FAR and height restrictions. Installation of solar systems would require a building permit and a list of solar energy system permits, including addresses and dates of issue, would be maintained at the Inspectional Services Department.

New development projects adjacent to existing solar systems would be encouraged to minimize shadow impacts on those solar systems. In addition, the impact of tree planting and landscape improvements on neighboring solar energy systems should also be considered.

Wind Energy Systems

The wind energy systems component of the Task Force zoning recommendations was adopted by the City Council in September 2009 and is now Section 11.40 of the Zoning Ordinance. 

Green Building Zoning Amendment - Ordinance 1333 

  • Genzyme Center -- Cambridge's first LEED Platinum building

    Genzyme Center -- Cambridge's first LEED Platinum building

  • Green Roof at 23 Sidney St, University Park

    Green Roof at 23 Sidney Street University Park

  • Police Station Green Roof

    Green roof at the Robert W. Healy Public Safety Facilities

For more information, please contact Iram Farooq, Senior Project Manager, ifarooq@cambridgema.gov at 617/349-4606 or John Bolduc, Environmental Planner, jbolduc@cambridgema.gov at 617/349-4628.