On Monday, daily newspaper the London Evening Standard (ES) published the contents of a leaked report prepared by British fire investigation company BRE to assist London's Metropolitan police in their investigation into the June 2017 fire that claimed 71 lives. The dossier details multiple failings of the 2014–16 renovation of Grenfell Tower that turned "a safe structure into a tinderbox," according to the article.
The 210-page interim investigation finds that while the combustible cladding on the 24-story building is largely at fault for the spreading of the fire—which started in a single refrigerator-freezer on the fourth floor—poorly cut and installed insulation gaps, faulty window frame installation, combustible insulation, and the absence of door closers also played critical roles in the quick spread of the blaze.
"Grenfell Tower, as it was originally built, appears to have been designed on the premise of providing very high levels of passive fire protection," BRE detailed in the pages published by ES. "The original façade of Grenfell Tower, comprising exposed concrete and, given its age, likely timber or metal frame windows, would not have provided a medium for dire spread up the external surface."
However, "deficiencies" in the construction and installation of the new façade and window frames failed to meet fire safety building regulations. The report reveals that the fire-stops were poorly installed—some upside down or back-to-front—which left a gap between the concrete surface and cladding of 1.9 inches rather than the requisite 0.98 inch. This, said the documents, provided a quick route for the fire to spread. The window frames were also installed leaving large gaps, and the spaces were filled with rubberized membrane, rigid foam insulation, and uPVC lightweight plastic panels, none of which could have provided more than 30 minutes of fire resistance.
BRE also found that the the tower lacked door closers, which would have ensured more apartment doors were closed and could have reduced fire and smoke escape from apartments into stairwell and elevator areas.
The inquiry determined that, due to the tower's height, the building should have been installed with a wet rising main rather than the dry raising main to assist firefighting; and the structure did not have the code-required sprinkler system and stairwells were 3 inches smaller than required.
Read select pages of the leaked report here.