Plans to build affordable housing atop a new parking ramp in downtown Rochester may have to be altered or scuttled after a preliminary engineering study determined the current structure wouldn’t support the additional load.

The city issued a statement Tuesday stating that the new 630-stall municipal parking facility, completed in April, might need more design and engineering work before housing could be built there.

The City Council recently approved a proposal from Common Bond to build affordable housing on what’s known as Ramp 6, which is part of the Destination Medical Center (DMC) project, a $5.6 billion public-private initiative to draw major investment to the city and remake Rochester into a destination in its own right.

Walker Consultants was hired to review the ramp and found it safe for its current use but concluded it might not be capable of supporting a housing addition. The review is preliminary and requires more testing, the city says.

City Administrator Steve Rymer said additional work may be required to support housing on the ramp, “and we are taking the necessary steps needed to better understand our options. The city of Rochester remains committed to affordable housing and the safety of our community and visitors.”

The city is awaiting an estimate for the expanded work.

Mayor Kim Norton, a strong proponent of affordable housing, said in an e-mail Tuesday that she is reserving comment on Ramp 6 until after the engineering report is complete.

She noted that the housing project is “not the only solution for affordable housing in Rochester! We continue to seek opportunities to provide housing options for all.”

City officials envision a pair of transit villages on the northwest and southeast sides of the city as part of the DMC project.

The villages — parking ramps with hundreds of housing units, some retail and a link to downtown via a circulator bus — would provide some of the thousands of additional parking spaces that projections say will be needed in Rochester by 2040. The city’s population is already growing at 1.5% annually, one of the state’s fastest rates.