The Times of London, citing leaked emails and meeting minutes, reported on Friday that Artelia UK, the project management consultants overseeing the refurbishment, had come under pressure to reduce costs.
One email from the Kensington and Chelsea Tenant Management Organization to Artelia discussed several options for slashing cladding costs and suggested that using cheaper aluminum composite panels, rather than panels made of zinc, could yield a “saving of £293,368,” about $380,000.
The BBC, which also cited documents it had obtained, reported that the money saved by using “aluminium cladding in lieu of zinc cladding” was part of a broader package of savings that brought down the total cost of the project to about £8.5 million from about £9.2 million.
Brian Meacham, an associate professor of fire engineering at Worcester Polytechnic Institute in Massachusetts, said that in general, the more expensive zinc cladding may have been less combustible because it has a less flammable insulation — some of it made of mineral wool fiber — than the aluminum composite cladding.
Aluminum ignites at a lower temperature than zinc, he said, noting, “Both metals will burn but it takes a hotter fire to ignite zinc.”
Grenfell Tower, which opened in 1974, is owned by the Royal Borough of Kensington and Chelsea but is managed by the Kensington and Chelsea Tenant Management Organization, a quasi-public entity. Its chief executive, Robert Black, stepped down on Friday, saying that he wished to focus on “assisting with the investigation and inquiry.”
At a meeting on Tuesday, the council’s Conservative leader, Mr. Paget-Brown, tried to exclude journalists. When he was forced to relent after receiving a court order, he prematurely ended the meeting after 20 minutes — earning him swift criticism from Mayor Sadiq Khan of London and from Sajid Javid, the secretary for communities and local government, who called for greater transparency.
The council’s top Labour leader, Robert Atkinson, called the way the meeting was handled “an absolute fiasco” and urged Mr. Paget-Brown to resign, according to a video of the proceedings published in the British news media. He also suggested that the Conservatives, a majority on the council, were trying to obfuscate the reality of what had happened at the tower block.
This week the government appointed Sir Martin Moore-Bick, a retired appellate judge with a background in commercial law, to lead an inquiry into the disaster. Mrs. May told members of Parliament that the investigation would “leave no stone unturned.”
Sir Martin — educated at Christ’s College, Cambridge, and lauded by his supporters for fair-mindedness and common sense — has come under scrutiny for some of his rulings. In 2014, he ruled that Westminster Council had the right to relocate a homeless woman, Titina Nzolameso, a mother of five with health problems, to an area 50 miles from London, even though she had previously lived in government-subsidized housing in Westminster and had argued that she needed her network of friends in London to help manage her situation. Britain’s Supreme Court overturned his decision.
The government is racing to test cladding on high-rise buildings across the country. As of Friday, 149 buildings in 45 areas had failed fire-safety tests, officials said.