That the City Council refer proposed changes to Cambridge Zoning Article 5.000.Rainwater & Flat Roof Zoning to the Ordinance Committee and the Planning Board for hearing and report

Proposal for converting flat concave roofs to a kind of greenhouse/glass porch Z.O. 5.55 In an effort to enhance the City’s commitment to mitigating environmental impacts of certain older types of residential buildings, namely so-called “triple-deckers”, while improving the City’s storm-water management, modifications to the applicable dimensional requirements of this Article 5.000, in particular regarding FAR and height limitations, may be authorized under the following circumstances: Residential buildings with a flat (concave) roof which may have poor upper-level thermal insulation and/or contribute to important heat island effects, or may suffer from the secondary effects of over- insulation, and on which a drain pipe collects water from the roof and combines it with household waste-water, discharging into a single outflow pipe to the municipal sewer line Provided that the resulting construction will: • significantly increase the thermal efficiency of the building • entirely eliminate rain water entry from the concerned roof into the sewer system, and that • said rain water is harvested on the property at the rate of 1/8 gallon per square foot of roof area, with the remainder dispersed at the ground to follow its natural path without direct encumbrance onto abutting properties, the construction of a partial structure relieved from the applicable FAR and height limit may be permitted within the following limits: • Additional height not to exceed 10 ft. above the existing roof line of the building • Footprint to be no closer than 3 feet from either long edge or rear side of the building, no less than 6 feet from front/street-side of building, and • Additional FAR not to exceed 20% of the existing FAR of the building. Furthermore, in enhancing alternative energy sources (Article 22), additional positive consideration will be given to projects that improve the: • installation of solar panels (impractical on residential flat roofs) • use of passive solar heating, convective cooling, seasonal shading with natural plants, • using rainwater at the roof level or floors below, • planting flowering bushes and vegetation attractive to pollinating insects at the roof level, and • harmonization of the new roof profile with the neighborhood architecture.