Dry rot has been discovered in other properties in Berkeley under new regulations introduced in response to the balcony collapse that killed five Irish students and an Irish-American woman in June.
The City of Berkeley in California introduced new ordinances in July setting out more stringent building rules after the fourth-floor balcony collapse at the Library Gardens apartment building on Kittredge Street.
The rules include a requirement forcing building owners to inspect outside balconies or decks for wood rot within six months.
City spokesman Matthai Chakko said property owners have found dry rot during these inspections.
“They will have to fix that,” he said. “That is exactly the type of problem that these ordinances were intended to solve.”
He was unable to say how many properties wood rot was discovered in because the first inspections were still being carried out.
Mr Chakko was speaking on Wednesday after President Michael D Higgins, on a visit to the city, planted a tree in a park in Berkeley, near the site of the June 16th tragedy, in honour of the victims.
The ordinances also include stricter requirements on the type of materials used in the construction of external balconies and forcing property owners to carry out inspections every three years.
Builders are also being forced to change designs to allow better ventilation to stop moisture building up and creating dry rot in wood. "Out of this horrible tragedy I hope we will see some positive action," Mayor Tom Bates said after planting another tree with Mr Higgins in the ceremony at Martin Luther King Jr Civic Park.
City inspectors said, in a report a week after the accident, that dry rot as a result of water damage caused the supporting joists to break.
Mr Bates said that city inspectors would be required, under the new rules, to be on site to ensure balconies are built to the proper code.
The state of California is also carrying out a study to see whether the state’s building code requires similar changes to their regulations.
Five 21-year-old Dublin students – Eimear Walsh, Eoghan Culligan, Lorcán Miller, Nick Schuster and Olivia Burke – and Ms Burke's Irish-American cousin Ashley Donohoe (22) were killed when the fourth-floor balcony they were standing on collapsed.
The Alameda County District Attorney Nancy O’Malley, responsible for prosecuting crime in Berkeley, is investigating the collapse to determine whether a crime was committed in the construction and maintenance of the balcony.
Ms O'Malley and her deputy, chief assistant district attorney Kevin Dunleavy, attended a ceremony in Berkeley on Wednesday where Mr Higgins honoured the first responders who rushed to the scene and the volunteers who helped afterwards.
Mr Bates described the tragedy as the most moving event of his life and said that it was “really important” for the President to visit.