Adaptive Reuse Conversion Proposed to Turn Downtown Office Towers Into 700+ Housing Units
DENVER, CO – A $300M+ redevelopment plan at 17th and California could transform two office towers into a 712-unit residential campus, backed by a major public-private financing strategy.
A concept plan has been submitted for 621–633 17th Street, proposing the adaptive reuse of two high-rise office towers into a 712-unit mixed-use residential development. The project would convert nearly an entire city block between 17th and 18th Streets into what developers describe as a vertical neighborhood in the heart of the city.
Rather than demolishing the existing buildings, the proposal focuses on adaptive reuse, preserving the exterior of both towers while transforming the interiors into housing, retail, and community space.
A Full Block Transformation
The site spans approximately 1.98 acres and includes two high-rise office towers (621 and 633 17th Street), a link building, and a 7-story parking garage.
Together, these structures would be unified into a single mixed-use campus. Plans call for 712 residential units, with a mix ranging from studios to five-bedroom apartments, a rare inclusion for Downtown projects that signals an effort to attract long-term residents and families.
Ground floor plans continue the emphasize of ground floor activation. A daycare facility is also planned, reinforcing the goal of creating a more complete residential environment downtown.
A High Stakes Financing Model
The project’s scale comes with a significant price tag, with total redevelopment costs estimated at over $300 million.
The financial strategy begins with a key acquisition. In April 2025, the development team acquired the two towers for just $3.2 million, a steep discount compared to past valuations exceeding $100 million. That low purchase price creates the financial foundation needed to support what could be $200M to $300M in conversion costs.
To move forward, the developer is seeking approximately $63 million in financing from the Denver Downtown Development Authority.
The proposed funding would be structured through tax-increment financing, allowing the loan to be repaid using future increases in property and sales tax revenue generated by the site.
City participation is considered critical, as traditional lenders often view large office-to-residential conversions as high risk without public backing.
In addition to public financing, the project is expected to rely on private equity and may also qualify for historic tax credits due to the buildings’ status within Denver’s Historic Preservation Program.
Why This Project Stands Out
While office-to-residential conversions are becoming more common, few match the scale of this proposal. The project stands out as a full-block redevelopment rather than a single building, with a broader mix of unit types including five-bedroom layouts, the integration of cultural and retail uses such as a museum, and the preservation of existing high-rise structures.
The site is also one of the most transit-connected locations in the city, directly across from the 18th and California light rail station and adjacent to the 16th Street pedestrian corridor.
What Comes Next
The project remains in the concept plan phase and will require multiple layers of approval.
A key milestone will be the outcome of the Downtown Development Authority financing request, which is considered a critical piece of the capital stack needed to secure full construction funding. The project has also faced early challenges, including complexities tied to existing ground leases, which can impact long-term financing.
If approved and financed, this would be one of the largest office-to-residential conversions in Denver and could play a major role in reshaping Downtown.
Development Team
Developer / Owner
The Luzzatto Company
Architect
HLW International
Civil Engineer
R&R Engineers
Structural / Facade Engineer
Thornton Tomasetti
MEP Engineer
MDP Engineering Group
General Contractor
The Beck Group
All project information was sourced from publicly available site plans, renderings, and permitting documents.
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All project information was sourced from publicly available site plans, renderings, and permitting documents.
3 minute read • A proposal at 621–633 17th Street could bring over 700 housing units to Downtown Denver through a massive office-to-residential conversion backed by a $300M+ redevelopment plan and a major public financing request.