LONDON — The high-rise apartment block in London that went up in flames Wednesday recently had an $11-million upgrade, triggering questions about how it became a blazing concrete coffin.
Experts said the 24-story building's "cladding" — an outer layer of panels added to improve its appearance and energy efficiency while keeping moisture out — would be among the focuses of the investigation into the deadly incident.
Authorities said Saturday that 58 people were missing and presumed dead — 30 of whom were confirmed dead. Met Police Commander Stuart Cundy warned that number may rise.
Witnesses described chunks of the cladding raining down on the area surrounding Grenfell Tower, which was built in 1974.
Matthew Needham-Laing, a litigation lawyer and expert in construction, said video showing the fast-moving fire was reminiscent of footage of recent blazes in Dubai where high-rise buildings were "engulfed in flames due to the cladding igniting."
"If the fire manages to break out and get into the cladding it melts the external metal, which is often no thicker than tinfoil, gets hold of the insulation material in the middle, and that ignites and starts to burn," Needham-Laing told the BBC.
These types of fires can climb up very quickly "so you get huge flames going up the inside of the cladding, which the firefighters can’t see and then it breaks out somewhere else," he added.
Needham-Laing noted that the first cladding fire was in 1991 but regulations "haven't kept pace with developments in materials." He warned that “thousands, probably tens of thousands, of buildings in the U.K. alone” feature similar cladding to that installed at Grenfell Tower.
The company that provided the cladding — Harley Facades — said it was made from aluminum composite material, which is two sheets of aluminum wrapping a non-aluminum core.
In a statement, Harley Facades' managing director Ray Bailey said "at this time, we are not aware of any link between the fire and the exterior cladding to the tower."
Construction firm Rydon was hired to carry out last year's refurbishment at the doomed high-rise — a project which included adding "rainscreen" cladding — on behalf of Kensington and Chelsea Tenant Management Organization (KCTMO). The building is owned by the local government.
Rydon said the project "met all required building regulations."
"We are working with the relevant authorities and emergency services and fully support their enquiries into the causes of this fire," it said in a statement.
The former president of the Royal Institute of British Architects (RIBA) said the U.K. has strict rules governing fire regulation in buildings so the blaze simply should not have moved so quickly.
"There should be a fire check on the cladding to prevent a fire that’s broken out inside [an apartment] from spreading externally from one flat to the one above,” said Owen Luder, who is the author of a practical guide for architects called “Keeping Out of Trouble.”
“It is impossible to say at this point what the cause was. But it should not have happened," he added. “A key question is what caused a fire of such intensity to spread so quickly? What caused the initial fire? Why was it so intense?”
Luder described Grenfell Tower as "almost a reinforced concrete frame with a central concrete lift shaft."
“When I first started building many, many years ago, you designed with a means of escape in the case of fire in mind,” said Luder. “The building should have been designed to prevent this from happening.”
The fire quickly became a political issue with Prime Minister Theresa May promising a "proper investigation."
She added: "'If there are any lessons to be learned they will be, and action will be taken."
Survivors also raised questions over the high-rise's "stay put" policy — which urged residents to shut their windows and doors and await rescue in the event of a fire.
"They say you're supposed to put a towel under the door and wait for rescue but I wasn't going to hang around," said Michael Paramasivan, who fled the 7th floor of the burning building with his partner and six-year-old stepdaughter. "I just got me and them out ... There was some kind of alarm but it was barely audible. It certainly wouldn't have woken you up."
In May 2016, a newsletter sent to residents by the management company KCTMO stated that the “smoke detection systems have been upgraded and extended.”
“If there is a fire which is not inside your own home, you are generally safest to stay put in your home to begin with; the fire brigade will arrive very quickly if a fire is reported,” the newsletter added. “The only reason you should leave your home is if the fire is inside your home.”
While it is law for new high-rise apartment blocks to have sprinkler systems installed, there is no requirement for them to be added to buildings as old at Grenfell Tower.
In November, a group called Grenfell Action Group said on its website that “only a catastrophic event will expose the ineptitude and incompetence of our landlord, the KCTMO, and bring an end to the dangerous living conditions and neglect of health and safety legislation that they inflict upon their tenants.”
David Collins, a former chairman of residents’ association, said he was not surprised by the deadly blaze given years of "mismanagement, neglect and bullying" by the property management company.
GALLERY: Fire Rages Through High-Rise Apartment Block
Speaking to NBC News' British partner ITV News, he said: “We’ve been talking about this kind of thing happening — we’ve said amongst ourselves a few times, [that] the worst that could happen. [It] would be a tragedy and then people would wake up to the mismanagement of this estate.”
He said that people who reported concerns “felt threatened, bullied or pressured” by KCTMO.
In a statement, KCTMO responded by saying it was “focusing on helping those residents and London Fire Brigade is investigating the safety of the tower's structure but we will issue a further statement in due course.”
Some local residents also criticized the initial response to the fire by emergency crews.
“There weren't enough engines, and they were asking people to stay inside,” a neighbor who identified himself as Abdul told ITV News.
He added that the fire department's ladders did not reach the higher floors of the building.
“I heard them screaming, ‘Just stay inside, don’t move!’” Abdul said, referring to the firefighters.
"I’m really upset," he added, his voice rising with emotion.
