After years of stop-and-go plans, the first from-scratch apartment building inside St. Louis’ Cortex innovation district is finally moving from renderings to reality.
Construction crews have broken ground on the Iris, a new mixed-use development at the corner of Clayton Avenue and South Sarah Street. Developer Keeley Properties is betting that putting apartments within strolling distance of labs, startups and City Foundry will turn the tech hub into more of a full-time neighborhood instead of a 9-to-5 destination.
According to the St. Louis Post-Dispatch, Keeley’s crews are already on site, with completion of the Iris targeted for 2028. The project had been stalled for years before finally getting shovels in the ground this month.
On its project page, Keeley brands the development as "Cortex k." and outlines a mixed-use plan of roughly 161 multifamily units paired with about 150,000 square feet of commercial space. The company pitches the site as an “anchor corner” that will link the Cortex district south along Sarah Street toward The Grove, a connection it highlights on its Keeley Properties listing.
Plans to bring apartments into Cortex have started and stalled multiple times as developers wrestled with rising interest rates and construction costs. Cortex officials have said those economic headwinds forced changes to both the design and the financing structure. In 2023, the developer and the district hit pause while they searched for alternate funding, leaving the project in limbo while, as Cortex’s public affairs team put it, they worked through “some potential design modifications and alternate financing mechanisms,” per the St. Louis Business Journal.
The Iris is rising inside the 200-acre Cortex innovation community, a dense cluster of university research, life-science labs and startups that has, until now, largely focused on office and lab space. Adding multifamily housing is designed to deepen the live-work ecosystem and cut commute times for researchers and engineers working in the district. Background on the district’s evolution is available on Wikipedia.
Timeline and neighborhood impact
Keeley and its construction team plan to build the Iris in phases, with finishing work and tenant move-ins stretching through 2028 under the current schedule. The mixed-use layout anticipates retail on the ground floor and office or lab-style commercial space on the upper levels, setting up more street activity near the City Foundry campus and the Cortex light-rail stop. The full program is detailed on the Keeley Properties pipeline page.
What to watch next
From here, the big milestones to watch will be city planning approvals, construction permits and any financing checkpoints as the Iris rises from dirt to finished building. Cortex organizers and local officials have argued that on-site housing could be a key tool in recruiting and retaining talent for campus jobs. Follow-up coverage will be keeping an eye on the unit mix, rent levels and any public subsidies associated with the development.
The St. Louis Post-Dispatch reports that crews are already active on the site this month, a visible sign that, after years of discussion, Cortex’s first apartment project is finally underway.
For nearby residents, the Iris promises new ground-floor shops and more foot traffic. For the Cortex district, it marks a significant step toward becoming a place where people not only clock in to work but also come home at night. We will keep tracking construction milestones and how the new apartments reshape the Midtown landscape.
