Dayana Francisquini, 26, and her children, six-year-old Thais, and Felipe, three, were among the victims of the fire at Lakanal House in Camberwell, south east London, in July 2009.
Helen Udoaka, 34, her three-week-old daughter Michelle and 31-year-old Catherine Hickman were also killed.
They all lived on the 11th floor.
The jury was asked to give a written narrative detailing its conclusions in each case.
The jury found that Lakanal House had inadequate fire protection to prevent the fire spreading from one flat to the next - Southwark Council and its contractors missed opportunities to check fire safety.
A lack of fire resistance around flat doors and around stairs led to the failure of compartmentation of up to 60 minutes. Fire risk assessment might have highlighted these failures and bought firefighters more time to save lives.