The Barrett, et al, Zoning Petition

Barrett, et al., Zoning Petition

Because a number of issues of concern have been raised by City statt, we are transmitting additional information regarding the Barrett, et al., Zoning Petition, which was passed to a second reading by the City Council on December 7, 2015 and could be adopted by a vote of the Council any time prior to February 17, 2016. Because of the concerns set forth below, City staff recommend that the Petition not be passed in its current form.

This would allow additional time for study and development of a proposed zoning amendment that could better address the likely adverse impacts of development of basement and cellar space for usable and habitable space.

In the alternative, if it is the will of the City Council to adopt the Petition, we recommend that the attached alternate version of the Petition, which is explained in detail below, be adopted in lieu of the Petition in its current form, as the alternate version includes measures designed to mitigate the adverse impacts of such development.

The Petition

There are two parts to the Petition: • Part A would allow the creation of new "accessory apartments" by special permit from the BZA within single-family and two-family homes throughout the city. In current zoning, accessory apartments are only allowed in exceptionally large single-family homes in Residence A-1 and A-2 zoning districts. We recommend that these amendments apply only to single-family homes.

Part B would allow all basement space to be excluded from Gross Floor Area calculations on a lot, either by right (in single-family and two-family homes) or by special permit (in multifamily, non-residential or mixed-use buildings). In current zoning, basement space is exempt from Gross Floor Area only if it is less than seven feet in ceiling height, or if it is used for parking or mechanical systems.

The information below addresses issues with the State Sanitary and Building Codes; concerns regarding encouraging greater use of basement space that is susceptible to flooding, which is a recurring problem throughout Cambridge that will be exacerbated by the effects of climate change; and other issues raised by City staff and the Planning Board and discussed by the Petitioner during the hearing process (see attached letter).

It should be noted that the proposed zoning changes would apply to every property in the city, and therefore it is not possible to consider its full range of impacts without undertaking a more comprehensive study.

State Code Issues

The State Building Code imposes requirements for multi-family dwellings, such as sprinklers and handicapped accessibility requirements, which are not applicable to two-family homes. Therefore, if an accessory apartment were created in an existing two-family dwelling, the Building Code requirements for multifamily dwellings would be triggered.

The Petitioner's letter suggests limiting the scope of accessory apartments to single-family homes, which would be accomplished by retaining the current definition of accessory apartments. This would avoid having the requirements for multi-family homes apply to existing two-family homes that add an accessory apartment. It should also be noted that the State Sanitary Code requires a minimum basement or cellar height of seven feet for all habitable uses.

Building permits cannot be issued for habitable space in basements with a height of less than seven feet.

Increased Risk of Flooding

The intent of Part B of the Petition is to encourage more usable space, both residential and non- residential, to be created below-grade in both existing and new buildings throughout the City. When Part A and Part B of the Petition are considered together, it raises the potential that additional below-grade apartment units might be created in neighborhoods that have predominantly single-family and two-family dwellings.

DPW is concerned about the proposal to encourage greater use of basement space that is susceptible to flooding, especially in light of the recently completed Climate Change Vulnerability Assessment (CCVA). DPW recommends that any zoning changes associated with increased use of basement space not proceed independent of the Climate Change Preparedness and Resilience Plan, which is currently being developed by the City based on the findings of the CCVA.

Some of the common risks associated with basement living space include overland flooding, sewer backups, and moisture leading to mold or other health concerns. These issues have all been the subject of discussion related to the Basement Housing Overlay Zoning in recent years. In some cases, appropriate measures can be taken to mitigate the risks.

For instance, the Basement Housing Overlay Zoning requires separated sewer / drainage lines and backflow prevention for all basement units within the overlay district, and various measures can be taken to prevent moisture or remove mold if it occurs. However, little can be done to avoid impacts on basement spaces when overland flooding occurs. This type of flooding is already a problem in many parts of the City and may be exacerbated over time with the effects of climate change.

These issues were identified in the Basement Housing Overlay Zoning discussion, resulting in the inclusion of the following measures as requirements for any special permit authorizing basement housing units in the overlay district: • All health and safety codes must be complied with, and the special permit may include conditions meant to mitigate risks to occupants; • Buildings must have fully separated sanitary sewage and storm drainage; 2 • Basement units must include backflow prevention devices and other measures deemed advisable by the City Engineer; and • An engineering report that assesses the history and risk of overland flooding must be submitted by an applicant and reviewed by the City Engineer in connection with any special permit application.

The assessed risk would be a factor in the decision made by the special permit granting authority.

In addition, through the Climate Change Preparedness and Resilience Plan, resiliency

recommendations for new buildings and existing buildings will be developed. These recommendations will include: • Measures to reduce the likelihood of flooding; backwater valves, barriers for floodwater entering below grade areas, etc.; and • Measures to reduce the impacts of flooding; raising mechanical equipment, using mold resistant building material, etc.

The Petitioner's letter presented to the Ordinance Committee on November 19, 2015 suggests modifying the Petition to "Provide guidelines for safe use and design and limit applicability to non Fema flood zone areas." Staff strongly agrees that flood risk factors should be a major consideration when new habitable basement space is created; however, there is no language to this effect in the Petition currently before the Council.