Stone Mill Lofts

Called Stone Mill Lofts, the project transformed the oldest still-standing mill building in Lawrence into a mixed-income residential complex. Remarkably, the project also meets today’s most ambitious energy codes as well as the National Park Service (NPS)’s stringent historic preservation guidelines. And as the dual crises of affordable housing shortages and climate change converge in cities and towns nationwide, Stone Mill Lofts has become an award-winning, nationally recognized case study in how to prioritize sustainability and decarbonization—both embodied and operational—while preserving landmark building assets and enhancing housing affordability.

Building on 55 years of adaptive reuse and historic preservation expertise, the TAT design team found innovative solutions to safeguard the landmark building’s unique historic characteristics while creating an airtight, ultra-efficient building envelope. Some of the key strategies included replacing original windows with NPS-approved triple-glazed historic replicas, as well as replacing more than 40 skylights. The team also applied continuous closed-cell foam insulation within residential units and in certain accessory use areas, while retaining the beautiful exposed stone in first-floor common areas and amenity spaces. All-new mechanicals include high-efficiency heat pumps and other electric systems that reduce greenhouse gas emissions by an estimated 33% compared to a typical apartment building.

The result is an adaptive reuse project that pushes the envelope for what preservation efforts can look like in the future. Featured in Fast Company and recognized with honors including a prestigious Architizer A+ Award and a Preservation Massachusetts 2025 Paul & Niki Tsongas Award, Stone Mill Lofts proves it’s possible to prioritize historic character and future-looking energy goals at the same time.