The Iris

Located in the NoMa neighborhood on the former site of the DC Housing Authority headquarters, the Iris is a 13-story, 380,000 sf residential building with 430 units and is the first building in the multi-phase 1133 North Capitol Development. The Iris features a mix of market rate and affordable housing units with studio, one-, two-, and three-bedroom options including open floor plans and nine-foot ceilings. The post-tensioned concrete building also features two levels of below-grade parking, co-working spaces, a courtyard, penthouse gym, pool, and a rooftop garden with views of the Capitol and Washington Monument.

Due to the contaminated soils at the site, a locally thickened mat foundation system was utilized to save on the need for long-term treatment of the water by the owner and save on unnecessary concrete at the foundation. Additionally, stand-alone wide shallow long-span post-tensioned beams supported off four concrete posts were designed to meet the needs of the architectural design eyebrow feature at the roof of the building.