Mayor Tom Bates yesterday said investigators believe the wood was not caulked and sealed properly at the time of construction and was damaged by moisture as a result.
The crowded fifth-floor balcony broke off an apartment building during a 21st-birthday party held by visiting Irish college students Tuesday, dumping 13 people 50 feet onto the pavement. In addition to the six killed, seven were seriously hurt.
Later in the day, however, the mayor said that the water-damage theory was speculation on his part and not an official conclusion, and that the investigation is still underway.
Building inspectors also determined another balcony at the Library Gardens apartment complex was "structurally unsafe and presented a collapse hazard," and it ordered it demolished.
Also Read
Segue Construction, the Library Gardens general contractor, was involved in two San Francisco Bay Area lawsuits in recent years involving allegations of dry rot and substandard balconies at condo and apartment projects in Millbrae and San Jose. Among other things, Segue was accused of improperly waterproofing balconies.
Both cases were settled in 2013 with Segue, developers and other parties agreeing to pay millions.
Segue spokesman Sam Singer said such litigation is common on large projects and "has no bearing on the tragedy in the Berkeley."