Construction of the Southwest light-rail line in the Kenilworth corridor of Minneapolis had little to do with the cracking that surfaced this winter in floors and walls of the nearby Cedar Isles condominium towers, according to a forensic engineering firm.

Socotec Engineering Inc. representatives told the Cedar Isles Condominium Association board Tuesday that 75% of the cracking resulted from "seasonal temperature swings" that caused the building to shift.

According to an executive summary presented to the board, the building's shift was made worse by the support system used to retrofit the condo towers from grain silos 40 years ago.

Construction of the nearby Southwest line was one of four factors contributing to 25% of the building's movement, according to Socotec. The others: wind, vibrations caused by nearby freight trains and deferred maintenance.

But not everyone agrees with that assessment — especially condo owners who have long feared that Southwest construction could damage their homes.

"To say that we disagree with the conclusions of the investigation would be an understatement," the condo association board said in a note to homeowners Wednesday.

"To claim that after 40 years of thermal expansion and contraction the building coincidentally suffered extensive damage due to that cause while severe shaking and drilling was occurring only feet away strains credulity," the board said.

Despite the cracks, Socotec said in its summary that the Cedar Isles condos are safe to inhabit and that work can resume on the tunnel with additional monitoring and oversight. Socotec representatives did not respond to a request for comment.

The 14.5-mile Southwest light-rail line will connect Target Field with Eden Prairie, snaking through a narrow area in Minneapolis between Lake of the Isles and Cedar Lake where plans call for a tunnel. Work on the half-mile tunnel was moving ahead when Cedar Isles residents discovered the cracks.

The Metropolitan Council, which is building the line, halted work on the tunnel and hired Socotec to investigate the cause of the damage at Cedar Isles.

A full report prepared by the nationally known firm had not been distributed to residents or to the public as of Wednesday, and the cost of the report had not yet been tallied, said Met Council spokeswoman Terri Dresen.

"Out of respect for the [condo] board and its residents, the Met Council will not comment on the findings at this time," Dresen said in a statement Wednesday.

The condo association's homeowners will be formally apprised of the findings this month. In the meantime, the condo board is expected to consider commissioning an independent review of Socotec's investigation.

The Met Council reported in January that the cost to build the Southwest line would increase by up to $550 million, to a maximum of $2.75 billion. One of the main reasons for the price increase is the complexity of building the Kenilworth tunnel.

The tunnel will be within a few feet of the condo towers, and construction will creep even closer to the complex once it resumes. When Southwest service begins in 2027, some 220 trains will pass the condos daily.

The condo board hosted a tour of the building Wednesday for elected officials. Those who went on the tour included Sen. Scott Dibble and Rep. Frank Hornstein, Minneapolis DFLers who lobbied for a review of the project by the state Office of the Legislative Auditor, and Sen. Scott Newman, R-Hutchinson, who chairs the Senate Transportation Finance and Policy Committee.

"We thought it would be better for people to come and get a first-hand look at the damage," board president Vanne Owens Hayes said.

"The floor plates are pulling away from the exterior walls in some places. It was unsettling to look at," said Dibble, who added he was "highly skeptical" of Socotec's findings.

Hornstein said Socotec's report should be made public.

The cost increases, frequent delays and change orders prompted Hornstein and Dibble to push for the project review, a move that garnered bipartisan support at the Capitol. Gov. Tim Walz signed the bill into law last month.