'A recipe for disaster' - New report into Berkeley balcony collapse finds problems with water-proofing during construction
As the second anniversary of the Berkeley balcony tragedy approaches a new report has highlighted errors in the waterproofing of the balcony when the building was built may have contributed to the catastrophic collapse.
Five Irish students and one Irish-American student lost their lives in the incident in June 2015. They were 21-year-olds Lorcan Miller, Eimear Walsh, Olivia Burke, Niccolai Schuster and Eoghan Culligan.
Irish-American Ashley Donohoe (22), who lived in California and was a cousin of Ms Burke's, also died in the collapse in the early hours of June 16.
A further seven Irish students were seriously injured when the balcony collapsed during a 21st birthday party. The students were spending a summer in California on a J1 visa.
Last month authorities revoked the construction license of the building's developer, Segue Construction, but no criminal charges have been brought.
Now a 145 page report has concluded that dry rot damage which had occurred along the top of the balcony’s deck joists resulted in the balcony being unable to support the load of 13 students, leading to its collapse.
The report outlines several errors in the way the balcony was waterproofed, which led to moisture saturation.
It notes that oriented strand board (OSB) was used in its construction instead of plywood, despite plywood being the originally planned material to use and there being no record of any authorisation or request to change to the cheaper OSB.
Research referenced in the report stated that once OSB becomes saturated with moisture, it does not release it very quickly.
The waterproofing of balconies at the Library Gardens apartments during time of construction didn’t begin until the 1st of August 2006 – more than nine months after the first mention of rainfall was made in the building’s construction log.
The report quoted official data showing that 38 inches of rainfall were recorded in the Berkley area between September 2005, when joists were first installed, and August 2006.
The construction log contains no reference to any method of framing protection for rainy weather being used.
The location of the dry rot along the top of the joists suggests the boards in direct contact with them were saturated by rainfall.
Waterlogging then occurred after a membrane required to keep out moisture was not installed by a sub-contractor.
Speaking to The Mercury News, the report’s author Robert Perry referred to the water sitting on top of the joists as “a recipe for disaster.”
“It’s rare that it’s so catastrophic in nature,” he said, adding that had no rain infiltrated the wood and been sealed inside, a collapse would have been “highly unlikely.”
The report states that there were no problems to be found with any documents relating to the construction’s design, and that a preliminary load analysis indicated that the imposed weight of 13 people was well within the balcony’s design limits.