The fourth-floor balcony at the Liberty Gardens apartment complex at 2020 Kittredge St. collapsed at 12:41 a.m. on June 16 during a party in Unit 405.
PHOTOS: Several killed in balcony collapse in Berkeley
The balcony was left hanging straight down along the building face. Of the six people killed, five were Irish nationals.
Construction on the five-story, 146-unit building was completed early in 2007 and inspectors at the time found the building, including the balcony, was up to code, according to a 10-page memo by city building and safety division manager Alex Roshal released Wednesday.
The balcony as constructed should have been able to support the weight of the 13 people who were apparently standing on it when it collapsed, city planning and development director Eric Angstadt said at a news conference.
But the balcony's joists, constructed of laminated veneer lumber, had sheered off 16-20 inches from the building face. Inspectors immediately noticed the joists that remained on the building were severely dry rotted and bits of dry rot debris were scattered on the balcony below, according to Roshal's memo.
The city ordered three other balconies in the building off-limits while inspectors determined whether they were at risk of collapse. The balcony directly below, which belonged to Unit 305, was determined to also be severely dry rotted and the city ordered it removed from the building the next day.
The other two balconies were determined to be constructed differently and not at risk of collapse, according to Roshal.
The balconies with the rotted joists were designed to be sealed from the elements, but moisture had somehow infiltrated both, according to Angstadt.
How the moisture got into the structure is beyond the scope of the city's inspection, but city staff is recommending the City Council take steps to prevent similar catastrophes in the future.
If passed, the amended building and housing codes as outlined in Roshal's memo would require all outdoor balconies and decks to be constructed from either naturally water-resistant wood, pressure-treated wood, corrosion-resistant steel or similar materials, regardless of whether they are sealed.
The interior of sealed decks would require some kind of ventilation to prevent rot if moisture was to get inside somehow.
The city would require inspections of all outdoor balconies in the first six months after passing the new regulations, and all would need to be inspected every five years in the future.
The City Council could take up the proposed new regulations as soon as July 14.
The five Irish nationals who were killed were all 21 years old and visiting the country on J-1 visas, which allows visitors to participate in work and study-based exchange programs.
They were identified as Olivia Burke, Eoghan Culligan, Niccolai Schuster, Lorcan Miller and Eimear Walsh.
The sixth victim was Rohnert Park resident Ashley Donohoe, 22, who had worked for the last eight months as a forensic assistant intern with the Sonoma County coroner's office.
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.