Lawrence Group Transforming St. Louis’ Iconic Mansion House Apartments While Honoring Mid-Century Modern Heritage

ST. LOUIS, MO — Lawrence Group has partnered with developer New + Found and ownership entity Coral Mountain Owner, LLC to breathe new life into downtown St. Louis’ iconic 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.

“Delivering a project of this scale requires careful sequencing and a high degree of coordination. We are focused on maintaining the integrity of the building’s original design while upgrading its infrastructure and systems to meet modern standards. Mansion House will be a model for how historic buildings can be adapted for today’s residential market,” said Greg Trost, Lawrence Group Associate Principal/Architect/Project Manager.

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.

“At Lawrence Group, we design spaces that feel as good to live in as they look. For Mansion House, our approach balances what to preserve with what to reimagine. Warm woods, clean lines, and community-focused layouts carry forward the timeless spirit of the original design,” said Lawrence Group Associate Principal/ Interior Design Project Manager Galen Vassar. “Fresh palettes, hospitality-inspired amenities, and resident-centered details bring it firmly into today where design is about connection, lifestyle, and everyday comfort. The result is a living experience that feels both familiar and fresh: rooted in character, yet responsive to the way residents live now.”

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.

About Lawrence Group 

Founded in 1983, Lawrence Group is an integrated planning and design firm headquartered in St. Louis, MO with professional staff in Texas, Florida and New York. Using the power of people with great ideas to bring their clients’ dreams to life, Lawrence Group specializes in architecture, interior design, master planning, landscape architecture and furniture procurement. Lawrence Groups’ talented team of professionals work nationally and locally in healthcare, education, retail, hospitality, housing, senior living and workplace with the common goal of providing legendary customer service.

To learn more about this powerful alignment of experience and expertise, visit www.thelawrencegroup.com or contact Director of Marketing Cindy Hausler, CPSM at cindy.hausler@thelawrencegroup.com.