Westminster coroner Dr Shirley Radcliffe gave the jury the choice of returning a narrative verdict or one of accidental death after a week-long inquest.
The decision angered the families of Michael Alexa and Jonathan Cloake who wanted to see an unlawful killing verdict returned.
The narrative verdict was critical of crane owner Falcon Cranes after its machine collapsed on the Barratt Homes site in 2006.
The inquest heard that the wrong manual was used to erect the crane which led to incorrect counter weights being used.
Specialist plant website vertikal.net reported that in a written statement read to the court, the jury representative said: “Both men died as a result of a crane collapse due to failure of the inner slew ring bolts due to overloading of the counterweight.
“The overloading was due to an incorrect manual being used in the erection of the crane.
“On the 25th July 2006, four inner slew ring bolts failed and all of the slew ring bolts were replaced. No investigation was undertaken as to the root cause of the bolt failure. On the 26th July 2006 the crane was returned to service.”
“At that time there was no adequate formalised process and procedure to allow for faults to be managed, escalated or investigated. In addition there was a vacuum of structured management in the service department.”