In response to the dual challenges of a regional housing shortage and the urgent need for climate resilience, Leggat McCall Properties has committed to an ambitious initiative: achieving Passive House certification across all 15 buildings of the Bunker Hill Housing redevelopment in Boston. This commitment was made proactively—before Massachusetts building codes required such standards—positioning the project as a model for low operational-carbon, equitable urban development.
The Bunker Hill Housing project will deliver 2,699 mixed-rate housing units, replacing outdated, low-density public housing with a vibrant, energy-efficient community. The development spans buildings ranging from six to ten stories, each designed to meet Passive House standards.
To address the scale of this undertaking, the project team developed a “kit of parts” strategy, consisting of precast concrete cores, 62 foot long CLT plank floors, spanning the entire width of the building, bearing upon a panelized, fully clad wall system. This approach creates an economy of scale that enables more housing to be delivered more efficiently and affordably.
Building M, a 100% affordable unit building and the first building in the development, served as the test case for this strategy. Through early-phase design coordination, performance mock up testing, and ongoing team coordination across the design and construction phases, the team established a replicable framework that integrates Passive House requirements with construction workflows that allow on site-efficiency. Building M was completed from slab-on-grade to occupancy in 16 months.
This presentation will explore how the Bunker Hill team leveraged early-phase design coordination, prefabrication, and Passive House certification to optimize both cost and operational carbon reduction. We will share lessons learned from Building M, including early-phase explorations and decisions around envelope detailing and construction sequencing.