Lawrence Group has partnered with developer New + Found and ownership entity Coral Mountain Owner, LLC to breathe new life into downtown St. Louis’ mid-century modern Mansion House apartments.
The $195 million project includes redevelopment of the vacant 415-unit Mansion House apartments and attached 558-space parking garage at 300 N. Fourth St. Built in 1966, the 29-story tower features 130 studio, 207 one-bedroom and 78 two-bedroom apartments with views of the adjacent Gateway Arch and Mississippi River.
Catalyst Opportunity Funds (Catalyst), a private equity firm focused on affordable and workforce housing, and New + Found broke ground on the project on Oct. 22, 2025. The renovated Mansion House is anticipated to open to residents in late spring 2027.
As the architect/interior designer on the project, Lawrence Group’s objective is to reposition Mansion House into fully renovated, market-rate, multifamily apartments through a systematic interior renovation that incorporates upgraded unit interiors, improved common areas, increased amenities, and complete MEPFP systems replacement. Plans also include a new dog park, upgrades to the fitness center, and a reimagined roof-top swimming pool and terrace providing panoramic views of the Gateway Arch and Riverfront.
Lawrence Group’s designers are focused on delivering high-efficiency apartments that respect the building’s mid-century modern heritage, its clean lines and panoramic views, while layering in new conveniences, shared community spaces, and lifestyle-driven amenities.
While downtown St. Louis has seen significant private investment in housing in recent years, much of the resulting development has targeted higher-income residents. Mansion House takes a different approach, bringing together impact investors, including capital from healthcare companies and banks, and public financing tools to maintain affordability for a broader range of families.
The majority of the units at Mansion House will be priced affordably for households earning under 80% of Area Median Income (AMI), a key feature of the project, with rents expected to start at $1,100 per month.
Lawrence Group/New + Found CEO Steve Smith characterized the Mansion House redevelopment as one of the largest residential investments in Downtown St. Louis in decades. The project, he says, will follow New + Found’s approach to preserving and modernizing significant architectural landmarks to meet current housing demands and protect Downtown St. Louis’ economic future.
PARIC is the general contractor on the project.
