However, Angstadt stopped short of saying the dry rot caused the collapse, adding the city will not making that determination. Angstadt made his comments at a news conference on Tuesday.
Angstadt went on to say that the balcony was up to code and properly designed to handle the load. He said this report is the conclusion of the city's only investigation.
#balconycollapse City of Berkeley to ask for inspections of all balconies within 6 months and then once every 5 years— Wayne Freedman (@WayneFreedman) June 23, 2015
On Tuesday morning, the city Building and Safety Division issued a summary of initial findings from the investigation of the fatal balcony failure a week ago.
In it, the inspectors noted that joists underlying the concrete balcony were extensively rotted at the place where the structure broke off, dropping 13 young adults five stories down to the street. The inspectors did not specifically say the rotten beams caused the collapse. But they are calling for more frequent inspections and several changes in the local building code to prevent balconies from being exposed to moisture.
#balconycollapse "How could this happen to a 10 year old bldg.?" "I don't know."— Wayne Freedman (@WayneFreedman) June 23, 2015
Staff members "believe that immediate adoption of the recommendations within this memo will be a step towards improving the safety of Berkeley residents in both existing buildings and those which will be built in the future," Berkeley's planning and development director Eric Angstadt wrote in the report.
VIDEO: Funeral held for two cousins killed in Berkeley balcony collapse
Berkeley Mayor Tom Bates said last week that rotted wooden beams might have caused the collapse. He later said the theory was speculation and a cause had not been officially determined.
Along with identifying dry rot in the support beams, inspectors also noted signs of decay involving the 4th floor balcony just below it.
The other two balconies in the 176-unit Library Gardens complex showed no signs of damage, they said. The joists on those structures did not extend from the building.
Meanwhile, the builder, Segue Construction, has issued this statement to ABC7 News: "Our concern remains for the families and loves ones of those who died in this tragic accident. We are carefully reviewing all findings of the ongoing inquiry, and continue to offer our assistance and cooperation to all investigating authorities."
Olivia Burke, Eoghan Culligan, Niccolai Schuster, Lorcan Miller and Eimear Walsh, all 21-year-olds from Ireland, and Ashley Donohoe, 22, of Rohnert Park, California, were killed June 16 when the balcony fell during a birthday party.
The seven other people on the balcony remained hospitalized.
PHOTOS: Several killed in balcony collapse in Berkeley
Click here to find out how you can support the Irish students currently in Berkeley during this difficult time.
Click here for a GoFundMe account for families of the Berkeley balcony collapse.