Third arson fire was most damaging to historic Stevens House in Minneapolis

The latest of three arson fires at the John H. Stevens House caused the most damage to the integrity of the historic building, requiring immediate measures to protect the structure, according to an engineer's report released Wednesday.

Arguably the most significant building relating to Minneapolis' origin story, the Stevens House in Minnehaha Park is in bad condition after a string of arsons between August and October. The report detailed extensive destruction to floor joists, studs, rafters and roof sheathing.

"The first two fire events caused only superficial damage to the building structural system; the loss of several east wall studs, loss of some wall sheathing and damage to three floor joists," according to the report from Mattson Macdonald Young structural engineers. "The third fire event cause[d] considerably more damage to the structural elements."

The report, which accompanied an assessment by MacDonald & Mack Architects, recommended "immediate temporary shoring to protect the most threatened parts of the structure." It notes that more permanent repairs should be made in the next two years.

The building is owned by the Minneapolis Park and Recreation Board. Agency representatives said last month that the building was covered under the agency's property insurance. But the cost of permanent repairs, and how much of it will be covered by insurance, is not yet known.

Investigators haven't said whether they have any suspects.

The agency installed a fence around the house after the first fire. But it wasn't enough to deter arsonists from damaging the property two more times. A taller, 8-foot fence now surrounds the property. The agency said that a mobile camera was placed on-site after the second fire as a deterrent.

"The first fire was of undetermined cause, and staff had no inkling there would be a second (let alone third) fire," Smothers wrote in a statement.

"This is very important history that needs to be preserved," Park Board President Meg Forney said in an October interview. "I just am super hopeful that our park police investigators are going to be successful in apprehending the individuals who are responsible for this damage."

The Park Board had allowed the exterior of the building to deteriorate before the fires, as evidenced by rotten wood, peeling paint and animal holes. It had planned to replace the roofs this year, followed by siding repairs in 2023. The engineer's report said the structure appeared to be in "good condition" preceding the fires.

John Stevens built the house on the banks of the Mississippi River in 1850, approximately where the downtown post office stands today. It became the "civic and social hub" of the new settlement, according to a plaque outside the property.

The Hennepin County Board held its first meeting there, and commissioners decided in the Stevens House to call the county seat "Minneapolis."

Thousands of schoolchildren pulled the Stevens House to Minnehaha Park in 1896, an event the Junior League of Minneapolis described as the "earliest example of historic preservation in Minneapolis."