Rayette Lofts: Structural Solutions for Urban Apartment Transformation

Project Overview

BKBM provided structural engineering services for the restoration and adaptive reuse of a seven-story concrete frame building in Saint Paul, MN. The project converted the former parking garage—originally constructed for office/manufacturing use—into a modern apartment complex following SHPO (State Historic Preservation Office) guidelines.

Project Highlights

  • Adaptive Reuse & Restoration:
    • Seven-story cast-in-place concrete structure transformed from former parking garage to residential apartments.
    • Roof top amenity space and deck incorporated to enhance building value and resident experience.
  • Specialized Engineering Solutions:
    • Original building adapted for parking garage use 16 years prior by removing floor slabs and installing concrete ramps.
    • Conversion to apartments required infilling these openings; a fire-rated, steel cold-formed joist system was selected for infill due to lighter weight and floor slab action changes.
    • Restoration and repair of original concrete floor slabs were necessary because of deterioration from previous roof leaks and salt accumulation.
  • Roof Structure & Mechanical Upgrades:
    • Existing roof slab did not have adequate capacity to support new amenity loads, so a new elevated structural steel system was installed for the deck and amenity space.
    • Additional structural steel installed to support rooftop mechanicals, emergency generator, and snow drift loads associated with the new rooftop structures.

Engineering Solutions

BKBM engineered creative structural solutions for adaptive reuse, addressing complex floor slab infills, restoration requirements, and new load paths for modern living and building systems. Careful analysis and detailing ensured compliance with historic preservation guidelines while delivering modern, durable, and safe housing.

Results & Impact

The restored and converted building now offers vibrant apartment living in a prominent St. Paul location. BKBM’s structural expertise preserved the building’s historic value while enabling sustainable, adaptive reuse that serves the city’s housing needs and revitalizes a significant urban structure.