The Old Chicago Main Post Office was a major hub for mail processing, housing heavy sorting equipment in a three-million-square-foot space.The building currently straddles the Congress Parkway. Extending this division forms a grand atrium.Removing every other floor accommodates large recycling and energy production equipment. The old building has low floor-to-floor heights. A large chimney on the southern half of the building exhausts the new energy equipment. The robustness of the existing structure enables a large rooftop arboretum.
The building’s location just west of the Loop permits easy waste delivery. Expanded loading docks accept waste rather than mail. The project also seeks to link the building to the pre-existing network of tunnels under the loop, allowing for pneumatic trash delivery. Additionally, pedestrian links lead to the restored art deco grand lobby and across the river via a “green” bridge and riverwalk.
Pedestrian routes take visitors throughout the building, allowing it to serve as an education center. These routes culminate at the rooftop year-round glass-enclosed arboretum. These two green house spaces serve as a public amenity for events or leisure and increases the building as a “destination” to visit. The glazing of the arboretum wraps down the southern façade of the existing structure. The interstitial space created between facades is utilized as a greenhouse to grow saplings in a compost generated by the waste processing in the building. The saplings are planted throughout Chicago.