The California Contractors State License Board, or CLSB, has released new information regarding the June 2015 balcony collapse investigation in the wake of a recent partial settlement between the victims of the balcony collapse and some of the defendants.

The information released showed that poor construction methods led to extensive water damage, one of the main causes of the collapse. The documents include a side-by-side comparison between the balcony design and how it was executed in reality.

“I’m not surprised that the report confirmed what we knew, which is that water intrusion was the main cause,” said Berkeley Mayor Jesse Arreguín.

In June 2015, a balcony collapse at the Library Gardens apartment complex — now renamed K Street Flats — killed six and injured seven.

Architect and contractor Robert Perry, who participated in the investigation, confirmed there were three critical instances of water damage that led to the balcony collapse: failure to pressure-treat the balcony supports, which would have helped with moist conditions; failure to substitute three layers of oriented strand board, or OSB, for 3/4-inch plywood; and failure to provide the protective coating specified in the balcony design, which could have prevented OSB moisture saturation.

Those who work in balcony construction do not recommend OSB because, according to Perry, if it gets wet for long periods of time, it tends to fall apart.

These were just some of the many elements in the design drawings neglected by Segue Construction, Inc.

According to Perry, the collapse was due to dry rot damage resulting from the changes made in construction. The investigation, however, has not been able to find why these changes occurred.

The CLSB revoked Segue Construction’s license in April, resolving the November 2016 accusation of Segue’s alleged negligence and disregard for following design plans. Segue Construction has since closed.

“It was a serious breach on their part and I’m pleased that their license was revoked,” said City Councilmember Kate Harrison.

In response to the incident, Berkeley introduced stricter building construction regulations and inspections on existing buildings. One of these amendments requires inspections of weather-exposed structures every three years. The following month after the collapse, all balconies were required to be inspected within the following six months, which affected about 6,000 buildings.

“We took immediate action to make sure this never happens again,” Arreguín said. “The work we did will save lives.”

The state is now following Berkeley’s lead, Arreguín said. Senate Bill 721, authored by State Sen. Jerry Hill, D-San Mateo, and coauthored by State Sen. Nancy Skinner, D-Berkeley, was introduced this year. The bill aims to prevent future balcony collapses by requiring inspections once every five years.

“This very tragic event illustrated some weaknesses in our previously existing building requirements,” Arreguín said. “This could have been avoided with better materials and better care to detail.”