THE balcony that collapsed catapulting five Irish students and one American to their deaths was only originally included in the San Francisco building design as a decorative feature.
The revelation came as a second balcony at the complex has been found to be structurally unsafe.
City of Berkeley official Matthai Chakko confirmed that engineers have ordered urgent safety works at the Library Gardens complex, which was only opened in 2007.
"A field investigation by building inspectors determined that the third-floor exterior balcony to Unit 305 at 2020 Kittredge was structurally unsafe and presented a collapse hazard," he said.
Police tape blocks off a section of Kittredge Street in front the Library Gardens apartment building where balcony collapsed in Berkeley, Calif., Wednesday, June 17, 2015. The balcony broke loose from the building during a 21st birthday party early Tuesday, killing several people and seriously injuring others. (AP Photo/Jeff Chiu)
"The Building and Safety Division ordered the property owner to remove the balcony within 24 hours.
"The balcony at Unit 305 is directly below the failed balcony at Unit 405."
The Herald has also learned that the balconies became the focus of a planning wrangle a decade ago between the City of Berkeley design review committee and the developers, Segue Ltd.
A February 21, 2002, briefing memo about the building's planning revealed City of Berkeley planners insisted they "need sample of balcony material" and that they would "prefer a lighter touch for two balconies on the Kittredge side".
It was one of these balconies that failed, throwing six students to their deaths and leaving seven others badly injured on Tuesday.
The City of Berkeley investigation is now focused on the water-proofing of eight critical wooden structural supports for the balcony.
Officials are also examining resident complaints about flooding at the complex in February 2013.
Both San Francisco civil engineers and residents of the Library Gardens complex off Kittredge Street in Berkeley yesterday said dry rot is feared to have degraded the timber supports.
The balconies were initially intended to be decorative when the plans for the complex were submitted for approval a decade ago.
Former Berkeley Design Review Committee official, Carrie Olson, who abstained from the approval vote, said the balconies were for decorative rather than practical purposes.
"(They were) definitely not large enough to be what the city would call an 'open space balcony,' where groups of people could stand outside," she said.
A flag flies at half mast at Leinster House, Dublin, where the Dail has gone into recess as a mark of respect to the six students who were killed in a balcony collapse in the US
However, the balconies were in daily use from when the complex opened with many residents opting to have breakfast on them to enjoy the San Francisco cityscape.
There were no use restrictions specified by law for the balconies. But only two apartments on each side of the building had a balcony.
Under a 57-page California planning regulation dating from 1998 and applied to the complex it emerged the balconies were simply required to have a structural capacity to handle 28kg (60lbs) per square foot.
All the complex balconies were built using timber rather than steel supports.
"The city will be retaining possession of the collapsed materials," Mr Chakko added.
"Once the damaged materials are removed from the building, they will be taken to a city facility and will remain under city control. City staff have also taken other steps to document the scene and the damage.
"Inspectors have been inside the unit, and they have completed an up-close, aerial investigation using cranes to examine the damage. Results of the city investigation are expected to take several days."
The building owners, Blackrock Ltd, and its property management company, Greystar, have issued statements of sympathy to the families of dead and injured students.
"Our hearts go out to the families and friends of the deceased and those injured in this tragic accident," a Greystar spokesperson said.
"The safety of our residents is our highest priority. We will be working with an independent structural engineer and local authorities to determine the cause of the accident."
Greystar operates in California, South Caroline and Texas and manages over 400,000 properties across the US.
Blackrock, based in New York, also extended its condolences.
The complex builders, Segue Ltd, are based about 40km from Berkeley and deal in residential developments.