Grenfell Tower cladding that may have led to fire was chosen to improve appearance of Kensington block of flats

The cladding that might have led to the horrifying blaze at Grenfell Tower was added partly to improve its appearance.

During a refurbishment aimed at regeneration last year, cladding was added to the sides of the building to update its look. The cladding then seems to have helped the fire spread around the building, allowing it to destroy almost the entirety of the structure and kill people inside.

And that cladding – a low-cost way of improving the front of the building – was chosen in part so that the tower would look better when seen from the conservation areas and luxury flats that surround north Kensington, according to planning documents, as well as to insulate it.

“Due to its height the tower is visible from the adjacent Avondale Conservation Area to the south and the Ladbroke Conservation Area to the east,” a planning document for the regeneration work reads. “The changes to the existing tower will improve its appearance especially when viewed from the surrounding area.”

The document, published in 2014 and providing a full report on the works, makes repeated reference to the “appearance of the area”. That is the justification for the material used on the outside of the building, which has since been claimed to have contributed to the horror.

The materials used were chosen “to accord with the development plan by ensuring that the character and appearance of the area are preserved and living conditions of those living near the development suitably protected,” according to the same report.

A number of conditions were attached to the 2014 decision to approve the plan – many of which related specifically to the material used in the cladding, so that the council could ensure the "living conditions of those living near the development" were "suitably protected".

The council noted that the cladding would also improve insulation, helping keep sound and cold out from the building, and improve ventilation. An environmental statement said that the "primary driver behind the refurbishment" was to address the insulation and air tightness.

"The reclad materials and new windows will represent a significant improvement to the environmental performance of the building and to its physical appearance," the planning application reads. "The design of the scheme as a whole has fully considered policy requirements, expectations and aspirations, fully taking into consideration the immediate and wider surroundings, particularly focussing on creating a wider environment that works as a coherent place," another part of the same document says.

That planning application concludes with a statement that "the development will provide significant improvements to the physical appearance of the Tower, as well as the environmental performance and the amenity of its residents".

Rydon, the company behind the refurbishment work, said the cladding and other changes had been made to help with "improving thermal insulation and modernising the exterior of the building".

A statement from Rydon after the work was finished noted that "rain screen cladding, replacement windows and curtain wall façades have been fitted giving the building a fresher, modern look".

That statement included a quote from Nick Paget-Brown, the leader of the council, who remarked on how happy he was to see "first-hand how the cladding has lifted the external appearance of the tower".

That public statement after the completion made no reference to insulation, only discussing the change in the external appearance of the building.

The refurbishment work that added the cladding cost £8.6m and finished in May last year. Both before and since that time, residents have repeatedly complained about the safety of the block, but were assured that there was no problem.

Councillor Judith Blakeman said questions would now be asked in the wake of those assurances.

“If the cladding was partly responsible for the fire we need to know what the specification for the cladding was and why it suddenly just went up (in flames) in about five minutes, because it should have been fire resistant, surely,” she said.

Ms Blakeman lives across the road and said she heard about the fire at 5am on the radio.

“I just rushed outside,” she said. “Neighbours had been watching it all night, they said the cladding went up like a nightdress by a fire – it just went whoosh.

“This is obviously part of the big refurbishment that finished about a year ago.”

The tower was built in 1974. But the refurbishment work brought a number of changes – new areas were added to the building, as well as the cladding.

Experts have repeatedly warned that the addition of cladding, which is regularly used to refresh old or unsightly buildings, can help spread fire. It can work like a chimney, they have warned, bringing up air that allows it to spread across a building quickly.

Chartered surveyor and fire expert Arnold Tarling, from Hindwoods, said the process can create a 25-30mm cavity between the cladding and the insulation.

“It produces a wind tunnel and also traps any burning material between the rain cladding and the building," he said.

“So had it been insulated per se, the insulation could fall off and fall away from the building, but this is all contained inside.”

He said not all insulation used in the process is the more expensive non-flammable type.

“So basically you have got a cavity with a fire spreading behind it," he added.

Angus Law, of the BRE Centre for Fire Safety Engineering at the University of Edinburgh, said: “Early media reports suggest that this event has similarities with other fires that have occurred recently around the world.”

He added: “The UK’s regulatory framework for tall residential buildings is intended to prevent the spread of fire between floors and between apartments.

“If spread of fire does occur, as has happened at Grenfell Tower, the consequences are often catastrophic.”

Construction firm Rydon, which carried out a £8.6m refurbishment of the exterior of Grenfell Tower last year, installing cladding and new windows, said its work “met all required building control, fire regulation, and health and safety standards.”