Survivors of the Berkeley balcony collapse and the parents of those who were killed have all begun legal proceedings against more than 30 companies involved with the California apartment complex.

They are seeking punitive damages from the building's owners and from those who were involved in its construction and maintenance.

Two law firms acting for the seven young people injured, and the parents of the six who were killed, all filed documents to the Superior Court of California in Alameda County late yesterday.

They are claiming the companies "cut corners" and had ignored "red flag warnings" that the balcony was unsafe.

San Francisco law firmWalkup, Melodia, Kelly, & Schoenberger, is representing 12 of the families.

The California-based parents of Ashley Donohoe, who are represented by Rains Lucia Stern, said that their clients were suing the companies involved in the hope that it would "bring to light the negligence and carelessness that caused this entirely avoidable tragedy", one that produced "so much pain and loss" both in the US and in Ireland.

In the legal papers filed, seen by RTÉ News, the families say they also want to "hold accountable" those responsible for the deaths and injuries, and to highlight their behaviour "so that a similar tragedy never occurs again".

Initial investigations by City of Berkeley officials found that severe rot in the wooden joists holding the balcony deck to the building had caused it to give way on the night of 16 June. 

Thirteen young people who were celebrating the 21st birthday of one of the injured, Aoife Beary, were standing on the balcony when it gave way.

Eimear Walsh, Olivia Burke, Ashley Donohoe, Eoghan Culligan, Lorcán Miller, and Niccolai Schuster all lost their lives when the fourth floor balcony collapsed beneath them.

In addition to Ms Beary, Hannah Waters, Clodagh Cogley, Sean Fahey, Conor Flynn, Jack Halpin and Niall Murray were all also injured.

They are described in the legal filings as "13 gifted, optimistic and high-achieving young people".

The lawyers for the families say the wood rot was caused by a "multitude of mistakes during design and construction", adding that when signs of a problem became evident "they were ignored".

The Walkup, Melodia, Kelly, & Schoenberger law firm also described how previous tenants had reported "large mushrooms" growing on the surface of the balcony between 2008 and 2010, just shortly after the building was constructed.

The families are suing the owners of the Library Gardens complex, the Blackrock investment companies, the Greystar property management company which operated and maintained the building, the construction company Segue Construction Inc and a number of subcontractors and other entities.

The facts of the case will be decided under California law. 

Families seek damages for 'wrongful deaths' of their children

In accordance with that law, the families and survivors are not seeking any set amount of damages, but rather that figure will be determined by a jury.

The legal actions will proceed as separate cases but the paperwork is almost identical, with one set for those seeking damages for their injuries, and the other set seeking "punitive damages" for the "wrongful deaths" of their children.

In the papers, the families argue that the "losses and harms" caused would never happened if the defendants had  "acted reasonably and prudently, complied with the standard of care in their professions, not cut corners and heeded one or more of the numerous "red flag" warnings that the balcony was unsafe in its design, construction, maintenance and foreseeable use".

The papers set out the scene of the tragedy, describing the young people as a "group of well-educated, hard-working, healthy and happy young men and women gathered to mark their friendship and celebrate the 21st birthday of plaintiff Aoife Beary".

They say that they had no "reason to know or suspect that a catastrophe was imminent", as they did not know that water-induced wood rot had destroyed the balcony joists.

The legal papers describe what happened next: "Suddenly and without warning, the balcony broke loose from the building, tumbled down and struck the third floor balcony directly below it. 

"The mechanics of the failure hurled the 13 students onto the cement footpath and asphalt pavement 40 feet below. 

"The unimaginable terror that each victim experienced during the fall was eclipsed by the carnage on the ground. 

"Six students died, and the seven survivors suffered substantial and lifelong physical and emotional injuries," the legal papers added.