The parents of the six students killed in last month’s apartment balcony collapse in Berkeley, California, have told city officials their proposed change to building rules, to inspect balconies every five years, is “completely inadequate,” calling for annual checks to be mandatory.

On June 16 the balcony at the Library Garden complex, on Kittredge Street, collapsed and feel 40 feet killing five Irish students and one Irish American. Seven other Irish students were also seriously injured. Immediately after the tragedy structural engineers reported that the balcony feel because of dry rot in the wooden support beams.

The lawyers of George and Jackie Donohue, whose daughter Ashley (22) and niece Olivia Burke (21) both died in the collapse, wrote to officials on Friday to challenge the recommendation made by building inspectors after the tragedy, that inspections be carried out every give years.

The Berkeley City Council will vote on these recommendation on Tuesday.

The Donohue family, who live in Rohnert Park, Berkeley, want a housing code that “requires annual maintenance inspections” of all exteriors and weather exposed wooden and metal balconies.

Lawyers, Rains Lucia Stern wrote in the letter “The Donohoe family wants to do everything in its power to ensure that this type of tragedy never occurs again.”

They also wrote that five-year inspections would create “the possibility that a building structure could be infested and compromised in the period between the required inspections.”

It has also emerged that the same balcony passed a private inspection, organized by the property, just last year. The construction company who built the complex, Segue Construction, has also paid out $26 million in damages in various court cases over the years.

Alameda County district attorney Nancy O'Malley is now conducting twin civil and criminal investigations into how eight timber balcony beams on a complex built in 2007 could severely rot and fail. A third investigation is being carried out by Contractors State License Board (CSLB), the body charged with regulating all builders operating in California.