What of the sister tower to the fallen Florida condo building?

In the hours immediately after much of the Champlain Towers South condominiums collapsed, the authorities evacuated two nearby buildings, an 18-story condominium tower and a seven-story hotel.

But no action had been taken by Friday at the fallen building’s nearly identical sister a few hundred yards up the beach — Champlain Towers North. Both buildings went up in 1981 in Surfside, Fla., just north of Miami Beach. The complex has a third building, Champlain Towers East, erected in 1994.

The mayor of Surfside, Charles W. Burkett, said on Friday afternoon that he was worried about the stability of the north building but that he did not feel “philosophically comfortable” ordering people to evacuate.

He was speaking at a town commission meeting called to formally declare a state of emergency in Surfside, which Mr. Burkett said would give the town access to state and federal funds.

“We have a lot of circumstantial evidence to lead us to believe that there could be issues at the sister building, Champlain Towers North,” Mr. Burkett said. “The layout of the building is the same as Champlain Towers South. It has the same name. It was probably built by the same builder, and it was probably built with the same materials. I can’t tell you, I can’t assure you, that the building is safe.”

Still, Mr. Burkett said he thought the decision to evacuate should be voluntary. He added that had not yet spoken with residents in the building.

Mr. Burkett, an independent, said he had decided on this approach after talking with elected officials in Washington and in Miami.

James McGuinness, who is in charge of Surfside’s building department, told the commissioners that construction crews had been working on the roof of the south building before it collapsed, but he said he saw no evidence that the roof work had contributed to the disaster.

“There was no inordinate amount of materials on the roof that would cause this building to collapse,” Mr. McGuinness said.

Mr. McGuinness said workers had been making repairs to the roof and to anchors on the corners that hold ropes used by window cleaners.

The condominium association had hired engineers to work on a review of the structural integrity of the building and its electrical systems, he said.

Miami-Dade County requires these inspections at intervals of 40 years, Mr. McGuinness said, but the work on the anchors on the roof were not related to the recertification process.

He said the town of Surfside had not yet received the 40-year inspection report from the building’s owners. Commissioners at the meeting said Surfside had no indication that anything was wrong with the building.