4240 Chestnut StUnder construction

A seven-story mixed-use building with 128 residential units is under construction at 4240 Chestnut Street, adding to the steady densification of University City's eastern edge. The project sits in CMX4 zoning, which allows for this kind of by-right mid-rise development without special approvals. The structure uses Type IA construction for its first two floors and Type IIIA above, separated by a three-hour horizontal assembly — a design detail that reflects the hybrid program of business and professional office spaces on the lower levels, accessory parking, and dwelling units above.

Rrg Chestnut Street LLC holds the property, and the project was cleared to build at the end of 2021. An amendment from mid-2023 revised the building's height upward, suggesting the developer saw room to push the envelope a bit further once the initial design was locked in. The building shares a fire-rated wall with the adjacent structure at 4245 Sansom, a 12-unit project that's also part of the recent development wave in the area.

Within a half-mile radius, nearly 300 units are either under construction or recently delivered, including a 145-unit project at 4401 Holden and a 72-unit building at 4050 Ludlow. This stretch of Chestnut has become a testing ground for mid-density residential, benefiting from proximity to the university corridor without the hard height limits and review scrutiny that accompany larger parcels closer to 30th Street Station.

The project's mix of office, parking, and residential suggests the developer is hedging against purely speculative residential plays, particularly in a neighborhood where ground-floor commercial tenants can be elusive. As sites like this one prove out the economics of seven-story CMX4 projects, expect similar assemblages along Chestnut and the surrounding grid to draw renewed attention from developers looking for predictable entitlements and manageable construction timelines.