Bunker Hill

This Boston condominium garage’s green roof using Omni Infinity Media serves the building’s residential community as an amenity space and simultaneously functions as a stormwater retention BMP (best management practice), capturing all runoff from the adjacent five-story residence.

After a 2016 fire destroyed this multi‑story condominium in Charlestown, Kistler and Knapp Builders acquired the property to rebuild. The project needed to meet Boston Water and Sewer Commission (BWSC) Sewer and Stormwater Requirements, including at a minimum infiltrating the first 1” of stormwater hitting the site’s impervious area.

Architecture firm Studio DRAW had been considering a green roof for the garage of the project as an amenity space and view improvement. Considering the BWSC requirements, Studio DRAW and engineer Hancock Associates assessed the feasibility of meeting stormwater requirements via the green roof, including structural calculations for the weight of the proposed stormwater BMP green roof. The project team determined that the Omni Infinity Media would best achieve the aesthetic and stormwater management goals with the least structural requirements.

The 1,016‑square‑foot, 12‑inch‑deep Omni Infinity Media provides approximately 840 cubic feet of stormwater volume control and adds only 35-45 pounds per square foot saturated weight to the structure. Compare that to a typical green roof media which would require 17-inch depth to achieve the same 840 cf of volume control but would add over 120 lbs/sf. Alternatively typical green roof media at 45 lbs/sf maximum weight (which is 6” deep) would offer less than 300 cf of volume control.