The Petroleum Building featured a drive-through bank teller, the city’s largest bar and a nuke-proof core.
The Petroleum Building at 16th Street and Broadway downtown. Nov. 25, 2025.
Kevin J. Beaty/Denverite
Another office-to-residential conversion is coming to Denver. The Petroleum Building, on the corner of 16th Street and Broadway, will become housing by summer 2027.
The Denver Housing Authority said the project is in its final stages of permitting and is expecting to break ground in spring 2026.
The Petroleum Building is a 14-story office building built in 1957 and designed by Charles D. Strong. Strong is responsible for many iconic buildings throughout Denver, especially on the University of Denver campus.
The tower on Broadway — sometimes known as the Denver Petroleum Club Building — was one of the tallest buildings in the city when it was completed. It once featured innovations like a drive-through bank teller and the city’s largest bar, and it was home to the influential Petroleum Club.
Built in the “international” style, it was said to have a core that could withstand an atomic blast from 2,000 feet away, according to a historical dossier. The so-called “atomic core” had foot-thick concrete walls, with stairs leading down to a stocked sub-basement that could double as a bunker.
Today, it boasts a Jimmy John’s on the first floor and a spot on the National Register of Historic Places.
And like many other office towers, the building has struggled with vacancies recently, according to Borst & Co., the developers behind the remodel.
The redevelopment was awarded a $14 million loan commitment from the Denver Downtown Development Authority. The redevelopment could cost close to $70 million total. The loan has a 10-year repayment term.
What’s the plan?
Twelve floors of the building will be converted to housing, while the ground floor and top floors will become amenity spaces for residents. The transformation will create 178 apartments in a mix of studios and layouts up to three bedrooms.
The building’s historic facade will be restored “close to its original form as a gateway into 16th Street,” according to Gensler. The building is at 110 16th St.
“Converting underutilized office buildings in Upper Downtown is a critical component of revitalizing the heart of Denver,” said Tim Borst, president of Borst & Co. and part owner of the Petroleum Building, in a press release. He said the project benefited from state and federal historical tax credits and support from Mayor Mike Johnston’s office.
The building also is owned by DellaCava Holdings. The two companies purchased the building in 2005. The architecture firm Gensler and the construction company PCL Construction also are working on the project.
The plan has been in the works since 2022. Borst and his company had been planning on selling the building, but the deal fell through when COVID-19 hit.
“We were already a little vacant … and then when COVID happened and there was a mass exodus downtown, our tenancy dropped significantly to the level we’re at now,” Borst told CPR News in 2022.
Office buildings are in trouble
Nearly 40 percent of downtown office space was vacant over the summer, part of a bigger downturn that city leaders hope is ending.
Denver officials have acknowledged that office buildings are unlikely to return to pre-pandemic occupancy levels. In recent years, local leaders have tried to encourage conversion projects, including through millions in grants.
The Denver City Council still must approve the loan from the DDA. The project has already secured a commitment for state historic tax credits, according to Borst & Co.
Last month, Denver City Council rejected the city’s plan to purchase and redevelop a former Goodyear auto repair shop into affordable housing. That plan was shot down because the funding would have come from the city’s emergency capital improvement funds.
But other conversions are underway, including one in the historic Denver Dry Goods building. The Denver Tech Center has also become a focus for redevelopment. A small developer also hopes to convert two towers on 17th Street.
The DDA’s loans are separate from the city’s regular budget. The DDA is a public body whose leaders are appointed by the city, and it is funded by a portion of downtown taxes.
