Geoffrey Osborne went under owing subcontractors and suppliers £25.86m.
More than 500 firms were left holding unpaid invoices when the famous industry name went into administration last month.
The scale of the firm’s debts have been revealed in an update from administrator RSM filed at Companies House.
Total debts at the time of Osborne’s collapse were £45m with cash also outstanding to HMRC, sister companies and Osborne employees.
Geoffrey Osborne’s demise followed an 18-month battle to save the firm which saw much of the original business offloaded in an attempt to save the core building business.
During this restructuring programme, Osborne sold its property management division, infrastructure business and offsite manufacturing arm securing the employment of over 850 jobs.
The proceeds of all three sales were reinvested, but failed to save the main business.