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News analysis: Five questions about Grenfell Tower that must be answered


With a criminal investigation under way and a public inquiry announced, the AJ puts forward five key questions about the causes of the tragic fire 


The residents of Grenfell Tower in west London had repeatedly warned of the potentially devastating effects of a fire before last week’s blaze. At the time of writing 79 people were dead or missing, presumed dead, as a result of the disaster. The exact cause of the fire at the 24-storey building in north Kensington, which had only recently undergone an £8.6 million refurbishment by Studio E Architects, remains unknown. Much more evidence will be needed before fingers can be pointed and, of course, there may have been multiple causes. Even so, the new cladding on this 1974 concrete block has already become a major focus of attention after eyewitnesses said the fire spread up the building’s exterior with alarming rapidity. Here are five key questions which will need to be answered.

Cladding drawing approved 1332326

Cladding drawing approved 1332326

One of the main aims of the refurbishment was to improve the building’s thermal performance through new external cladding. In its designs, Studio E Architects, working with contractor Rydon, specified an insulation system comprising Celotex FR5000 insulation board attached to a timber backing. The drawings also specified a Reynobond aluminium composite material (ACM) rainscreen panel to be installed 50mm in front of the insulation. Rainscreen cladding panels can come with either a polyethylene core or a slightly more expensive, honeycombed mineral core, which is more fire-resistant. 

According to a report in The Guardian, at Grenfell, the construction team used the cheaper panels. These are prohibited on high-rise buildings in the USA and – according to the Department for Communities and Local Government (DCLG) – also breach the UK’s Building Regulations 2010, which restrict their use on buildings over 18m tall.

Earlier this week chancellor Philip Hammond said a criminal investigation would be launched to investigate these possible breaches – in particular discrepancies with Part B (fire safety) Volume 2, Paragraphs 12.5-12.9, which state that cladding and insulation on buildings over 18m tall should be of limited combustibility. This is defined further in Table A7.

2. If this cladding method breached the regs, why was it used at Grenfell Tower?

Grenfell tower ©harley facades c1059 complete 4

Grenfell tower ©harley facades c1059 complete 4

Source: Harley Facades

This will be a key question for the Met’s criminal investigation and the public inquiry but, at the time of writing on Monday (19 June), Kensington and Chelsea Council remained unwilling or unable to answer basic questions put to its press office five days previously, including if and when Studio E’s project was granted Building Regulations approval and when exactly Grenfell Tower last had a fire risk assessment.

What is known is that fire experts have long claimed that Part B is inadequate and open to exploitation. The document has not been properly reviewed since 2006 and, in 2015, a survey by the Fire Sector Federation, which represents fire and rescue organisations, found that 92 per cent of its members believed that the regulations were ‘long overdue an overhaul’.

In the UK, products are tested on an individual basis, rather than in combination with other building components. This contrasts with the testing regime in the Middle East. Following a series of serious fires in high-rise buildings there linked to the use of panels containing polyethylene – the same cladding material apparently fitted at Grenfell Tower – the UAE banned the material and ruled that components must be fire-tested alongside other components.

Konstantinos Tsavdaridis, associate professor of structural engineering at the University of Leeds, told The Times that the UK needed to adopt such a system, adding: ‘You may have very good material indeed. But if you install it as part of a system with gaps and voids, the smoke and the heat can pass through and create a chimney effect, funnelling flames to the floors above. That’s what happened at Grenfell Tower.’

The role of procurement and whether value engineering was at play will also be in the spotlight, as will the government’s war on red tape and so-called ‘health and safety culture’ and whether this drive helped allow rules to be broken or bent. After speaking to affected residents last Sunday, London mayor Sadiq Khan said: ‘To those who think rules, regulations, health and safety investment, are a bad thing, I say come to Grenfell Tower, come and meet the wonderful people I have met and remember those who have lost their life in a preventable accident that didn’t need to happen.

‘The tragedy we have seen is the consequence of mistakes and neglect from politicians, from the council, and the government.’

3. Could the declining role of architects have played a part in this tragedy?

Proposed south elevation revised drawing 1094421

Proposed south elevation revised drawing 1094421

The answer to this will of course depend on the exact cause of the fire and thus on the outcomes of the public inquiry. However, there is a suspicion that there is no longer a single competent professional such as an architect or engineer who has responsibility for specifying materials and – alongside the building control and fire officers – ensuring such materials, or a safe and legal alternative, are used and correctly installed. 

Instead, the argument goes, responsibility for risk has been spread around to the point where no-one knows where responsibility lies. In a recent opinion piece for The Guardian in response to the Grenfell Tower fire, architect Deon Lombard – a former project director at tp bennett who has worked on major refurbishment projects and on residential towers – wrote: ‘In the past, architects have specified construction materials and have then been in a position to ensure that the specified materials were used. This is increasingly not the case as performance specifications enable alternative materials to be used, often selected by the developer, contractor or subcontractors. 

‘With architects now seldom having the authority to insist on specific products being used, there is a tendency to go for cheaper materials, without necessarily understanding the impact or knock-on effect.’

RIBA Council member George Oldham – Newcastle upon Tyne’s city architect from 1979 till 1990 – told the AJ that ‘something has been lost’ in the move away from filling such positions, pointing out that his role had involved a wide range of responsibilities, including fire risk and maintenance of buildings.

He said: ‘There has been a shift from public sector control of the design and building process to something which is more or less a free-for-all.’

Statement from Studio E

We are deeply shocked and distressed over news of the devastating fire at Grenfell Tower. 

Our thoughts are with those that have been affected by this tragic incident, together with all of their relatives and friends.

Given the ongoing nature of the incident it would be inappropriate for us to comment or speculate further at this stage. We will be available to assist the relevant authorities as and when we are required.

4. Are there any other buildings at risk?



Source: ChiralJon

According to the DCLG, there are 4,000 similar residential tower blocks in the UK – many of them owned by local authorities. 

Councils around the country including London boroughs, Sheffield, Leeds and Manchester are urgently carrying out fire safety checks while tower block residents in four major Scottish cities – Edinburgh, Glasgow, Aberdeen and Dundee – were quickly reassured by the authorities that the cladding believed to have been used at Grenfell Tower had not been used on their buildings. 

In addition, at least one architecture practice is internally reviewing its designs for tower blocks and the building materials used.

Simon Bayliss, managing partner at HTA, said: ‘We’ve set up a technical group across our various architecture studios and different teams, so we can represent all of the buildings we have built recently or are currently building. 

‘We will be looking into the implications of the detailing, the packages we’ve prepared, our role on the projects, and preparing ourselves to work with the clients and the contractors should they need any assistance.’

Bayliss, who lived in a 20-storey tower block for eight years, said that HTA had yet to establish whether any of its schemes used the same cladding as Grenfell Tower.

He pointed out that a 2012 fire at a HTA-designed 22-storey tower block in the Chalcots Estate, north London, which had used aluminium cladding, had not spread to other floors. 

‘We need to look at every single one individually and make sure that the right things were done,’ he said.

Prior to the Grenfell Tower fire, safety checks on tower blocks appear to have been in decline.  

According to figures published in last weekend’s Sunday People, fire safety checks at tower blocks and commercial buildings fell 25 per cent in the five years from 2011 to 2016, from 84,575 to 63,201. Worryingly, the cladding used in Grenfell Tower is not restricted to residential buildings either. The Times reported that £553 million of public sector money has been spent fitting buildings with similar external cladding, including schools, hospitals and leisure centres.

5. What needs to be done immediately to make sure post-war, high-rise residential blocks are safe?

Ampthill estate by nico hogg

Ampthill estate by nico hogg

Source: Nico Hogg

Ampthill Estate in Camden

Among the most extreme solutions is give up on these buildings and to simply flatten them. Writing in last weekend’s Observer, mayor Khan wrote: ‘It may well be the defining outcome of this tragedy that the worst mistakes of the 1960s and 1970s are systematically torn down.’

Others have suggested less drastic measures, including the retrofitting of sprinklers to all high-rise residential blocks, a recommendation made in 2012 by the coroner at the Shirley Towers inquest.

At present, only towers built in England since 2007 and above 30m high have to have sprinklers fitted. Their effectiveness was praised in 2015 by a spokesman for the Chief Fire Officers Association, who maintained that no-one had died in any fire in the UK in a building with a ‘properly installed sprinkler system working the way it’s meant to’.

However, others point out that it will take months to fit sprinklers to all vulnerable towers and call for far more urgent action.

Leading architect Rab Bennetts said: ‘We cannot wait. We need to get moving on several thousand towers. The government needs to ensure there are fire extinguishers and smoke alarms on every level, they need to make sure fire doors work properly and the seals are good and they need to  ensure that flammable clutter and rubbish isn’t left around on landings.

‘There are thousands of people in these blocks and they need everything done fast to ensure they’re ok.’


  • April 1991 Cladding cited as a key factor in a fire at Knowsley Heights, Liverpool 
  • June 1999 One person dies in a tower block fire in Garnock Court in Irvine, Scotland. The cladding is cited as a factor
  • 2005 Scotland requires sprinklers in all new-build tower blocks above18m
  • 2006 The government insists on sprinklers in new-build tower blocks of flats higher than 30m
  • July 2009 Six people die in a fire in Lakanal House, south London. The coroner says that the Building Regulations should ‘provide clear guidance’ with regard to the ‘external fire spread’ on buildings
  • April 2010 Two firemen are killed fighting a fire in Shirley Towers, Southampton
  • November 2010 Fifty-eight people die in a fire in a 28-storey block of flats in Shanghai. External insulating material is cited as a possible cause
  • 2012 Shirley Towers inquest. Coroner recommends sprinklers should be fitted to existing residential tower blocks
  • March 2013 Lakanal House inquest recommends retrofitting sprinklers to existing tower blocks
  • January 2014 Planning permission is granted for the £10 million refurbishment of Grenfell Tower, including new external cladding. Completed in 2016
  • December 2015 Cladding is cited as a cause for the spread of a fire at the 63-storey Address Hotel in Dubai
  • January 2016 Legislation introduced in Wales requires sprinklers in every new home
  • November 2016 Grenfell Action Group warns that the block’s manager KCTMO is ‘playing with fire’ and ‘only a catastrophic event will expose the ineptitude and incompetence of our landlord’
  • 14 June 2017 Fire breaks out on the fourth floor of Grenfell Tower

Readers' comments (14)

  • The horrific images of the tower burning naturally focus attention on the cladding, but there are other questions to be clarified.
    The morning after the fire the BBC quoted residents (I think) as claiming the the fire brigade couldn't use the dry riser, and that there were difficulties in isolating the gas supply - and there's also the question of the speed at which the escape routes became smoke logged.
    On a wider scale, there are surely questions about whether the building control system of design and construction approvals is as effective as it should be - and whether the level of real (as opposed to theoretical) quality assurance provided by the tradition of employing a wide awake clerk of works who was completely independent of the contractors has fallen by the wayside.
    There seems to be evidence to support these concerns, for example the Scottish schools construction scandal, and the extraordinary and not fully explained failure of the almost new Dartington Primary School buildings - and how can 'design and build' contracts be ensured to be free of compromises on quality?

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  • Thank you AJ !

    I might have put as the top question, Why in a multi-million pound "refurb" was apparently no consideration given to ensuring a working fire alarm system, two ways out at ground floor, check & improve all fire precautions, a pressurised fire escape stair and so on.
    One would therefore begin to question how negligent the landlords were.

    Secondly, One should question whether the over-cladding system as installed was SAFE.
    We all know Building Regs were not updated after the Coroner's report for Lakanal. Successive minister refused to act. In parliament a bill to require all rented accommodation to be "fit-for-purpose" was voted down by over a hundred Tory landlords.
    We all also know why these materials have been banned in Germany.
    No hiding behind lousy Regs.

    What should be done? Immediately evacuate all over-clad flat blocks. Stop over-cladding except with incombustible, non-plastic insulants.

    Remaining tower blocks are likely safe if not subjected to a catastrophic extra fire load / hazard of cladding. Especially if they have fire alarms and so on. Although the idea of a one stair block 24 storeys high does give me worries.

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  • Just as architects' deflected attention from the real issue towards the need for p. a. systems in staircases after the 11th of September 2001 (S.O.M), the simple and basic question is not addressed here either. Maybe because it would upset too many apple carts.
    Is high-rise dangerous by its very nature?
    I am of the opinion that it is.
    Below 6 floors people can still be rescued from their windows, and facades can be hosed-down. How many more will die with their beautiful views before 6 floors, or preferably less, becomes the maximum allowed buildable height.
    An immediate moratorium should be imposed on all high-rise building to protect lives.

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  • Oh please be realistic Colum, houses are dangerous too, when we forget basic fire prevention measures, or add fire load like soft furnishings, or the gas is badly installed, or even a small domestic fire …
    New York has many high rises, yet they don't burn down all the time, because even in regulation free USA they are very keen on fire protection measures.
    We have the knowledge to make high rise work, but those in charge do not have the will.

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  • David Berridge is about the only one who has put is finger on the key issue WHY WAS THERE NO EFFICIENT (IF AT ALL) FIRE WARNING SYSTEM. It is clear people were trapped in their flats not aware until to late there was a fire consuming the block.

    The other issues will all examined detail and the contribution Fire Regs, the renovation cladding, the management of the block when it has been established 1. what caused this catastrophic fire and 2. why did it spread so rapidly through the block when the fire fighters were on the scene within 6 minutes. Finally high rise residential blocks can be designed, built and managed properly, but they must be designed, built and amanged properly. Owen Luder CBE PPRIBA

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  • Industry Professional

    Re the cladding, I've read the Building Regulations over and over on this, and peviously when designing, with an extremely strict Building Control Officer monitoring my designs. The interpretation is Reynobond PE is ok under the regs because neither they nor the tests went far enough to cope with new materials. Nit picking on is the PU core classed as insulation is taking interpretation of the hastily written and ambiguous regs to the extreme that a normal professional would not. You can nit pick the over complex wording as much as you like and Reynobond PE with Celotex fire inhibiting insulation can be justified by interpretation. The techiques have caught up and overtaken the regs ability to cope with them. Notwithstanding other issues, the real issue lies here: http://www.londonlovesbusiness.com/business-news/business/disturbing-details-about-grenfell-tower-negligence-revealed/16371.article?utm_source=Sign-Up.to&utm_medium=email&utm_campaign=17719-393380-Campaign+-+20%2F06%2F2017+AM

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  • Fire alarm provision is a subject often discussed incorrectly in the media, if I could provide some clarity as a designer.

    Residential buildings require different fire alarm solutions to commercial buildings. Whilst it may be acceptable to evacuate a commercial building even if the alarm is false, evacuating hundreds of people in the middle of the night every single time someone burns a piece of toast would not be. Particularly within a high rise where upon fire alarm activation the lifts are programmed to be locked out of public use, evacuating hundreds of occupants many of them elderly or infirm down 22 flights of stairs would be extremely hazardous.

    As a result the fire alarms are configured in MOST residential high rise developments to alarm only with the affected apartment and for other residents to remain within their own apartment . The 1hr fire compartment around the affected apartment should provide sufficient time for the alarm to be raised, the fire service to locate the fire and either extinguish it or under extreme circumstances carry out a controlled and phased evacuation of the building.

    There are around 1,000 tower block fires in London alone and in 999 instances the 'Stay Put' policy works perfectly, protecting the occupants and allowing the fire service unrestricted access to locate the fire with damage limited usually to one apartment. This certainly would not be the case if the fire service also had to deal with the chaos of hundreds of residents blocking the corridors and single escape stair delaying them access.

    However for this solution to work, it is imperative that the spread of fire between compartments is controlled. Unfortunately this was not the case at Grenfell Tower and identifying why should be the immediate focus of investigators.

    It is also important to note that sprinklers fitted within a residential development (domestic sprinklers) are very different to those fitted within a commercial building and offer much lower performance and capacity. Simultaneous fires in a large number of apartments such as here caused by spread of fire externally would quickly overwhelm a domestic sprinkler system.

    Domestic sprinkler systems rely on the buildings general cold water pipework, pumps and pressure to deliver some water to a fire. A commercial sprinkler system has dedicated water supply & pipework, massively powerful pumps and backup power supplies and would be incredibly difficult, time consuming and expensive to retrofit into an existing tower.

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  • Celotex commissioned a fire test for the FR5000 board, in order to establish its use in buildings over 18m high. It passed. It is not clear who did this test, and what governing standards were used, if any.

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  • Thermal pannels Celotex FR5000 seem to have similar UK fire specifications than Reynobond PE, except in part 6*

    Reynobond PE:
    Fire propagation BS 476, part 6: class 0
    Surface spread of flame BS 476, part 7: class 1

    Celotex FR5000:
    Fire propagation BS 476, Part 6: Pass (*)
    Surface spread of flame BS 476, Part 7: Class 1

    *No class?? What does it mean?
    Has been considered the reaction and contribution to fire spread of that material?


    Good info, but I miss comparative reference to EU regulations before to Middle East, since UK is in Europe, even I assume UK did not join EU standards.

    About chimney effect of air camber, an suggestion: it can be blocked in fire case if intumescent coat is put in one internal face, even in horitzontal bands.

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  • Though all material provisions related to safety must be in place, other matters should be in place as well. Shouldn't towers of any size run fire drills at regular intervals for the benefit of all those concerned? Grenfell caused the loss of a number of people. How far this loss could have been avoided should be the topic of a reflective discussion to take stock of the state of other towers still standing intact and see if people are safe in the event of a similar tragic occurrence.

    Fire drills should be professionally led at different times of the year and different times of the day. Uncomfortable, but inevitable if anyone wants to remain alive and kicking. Fire is one of the worst nightmares one can experience. It strikes when least expected. But having the right practical training reduces silly mistakes, arms the residents with practical fire fighting skills at least in certain circumstances (such as small fires at home) and prepares the people with the right skills and mental alertness for such eventualities.

    Moreover, a fire drill highlights any shortcomings in the escape process and in the people's reaction - both residents and passers-by. As the saying goes: Precaution is better than cure.

    Joseph Bonello

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