Key West building officials are monitoring a survey of balconies on one of the island's most recognizable properties, following a report that one of the terraces was crumbling onto the one below.

Only one balcony had clearly visible problems at 1800 Atlantic Blvd., a four-story concrete condominium of 168 units, where an ocean-view three-bedroom apartment recently sold for $1.2 million.

John Woodson, director of the Key West Building Department, said the condominium's management and board have been cooperating with his agency's investigation, which followed the report of concrete from one apartment falling down onto another. That apartment, an unoccupied transient rental, was declared unfit for habitation by a fire marshal. An investigation by an engineering firm hired by the condo board followed, resulting in findings that would necessitate what was described as costly repairs.

No other balconies appeared in imminent danger of falling, engineers told building management and city officials. All balconies except for the one are being used and at the moment were deemed safe.

A second opinion was sought by the board, and the results of that engineer's investigation should be announced either Friday or Saturday when the board meets.

The complex is made up of three buildings, which maintain a commanding presence at Atlantic Boulevard and Bertha Street.

"We are trying," said condo board President Bill Brasuell. "This is stuff that happens to all reinforced concrete buildings in coastal areas. The iron rusts and causes the concrete to pop off and weakens parts of the structure."

Last year, the condo shareholders replaced 52 foundation columns that had suffered wear and damage over the 27-year lifespan of the buildings.

Brasuell said he expects the final engineer's report will contain information that there are structural problems with other balconies, though he had no idea yet how many.

When extensive, expensive work is required due to unusual circumstances, Brasuell said in response to questions, all of the condo's shareholders shoulder the burden of repairs.

In a case like this, he said, that could mean costs to each unit owner in the tens of thousands of dollars.

When work is that extensive and an owner cannot afford to pay, Brasuell said, the debt is usually collected through a lien placed on the unit, in anticipation of future sale.

Engineers say that one cause of such failings is the entrance of water, particularly from a salty environment like the Keys, into the concrete. This can rust the steel framing inside, and eventually it cannot support the weight of the concrete around it, resulting in collapse.

Candy Van Duft, the building's community association manager, said sale prices of the various condos vary, and that there are other amenities at 1800 Atlantic in addition to the views..

"From the outside it is rather stark looking," she said of the complex. "But inside it's like a big beautiful lush tropical garden in the courtyard, with an Olympic-sized swimming pool, Jacuzzi and saunas in the restrooms. There are two regular asphalt tennis courts and one clay court."

Van Duft said she is working closely with the city and the condo board on the balcony issue.

jdesantis@keysnews.com