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One thing I would like to know about arises from a comment I heard by a Grenfell resident who escaped from a flat some way up the building. He said that the first he knew about the fire was when smoke seemed to start coming out of the wall below and around the window(s). This suggested to me that perhaps, when the insulation was installed, this caused the windows to be recessed into the walls, by the thickness of the insulation and cladding, restricting the view, which led me to think that maybe the window frames were moved outwards so they were again flush with the walls. This would mean that the "exterior" insulation would now be inside the building around the windows. Also, the windows would have to be fixed in their new positions, and having seen how new windows in our son's house in England were installed, I just wondered if they could have been held in place with the ubiquitous polyurethane foam. Doesn't bear thinking about, and it's all disappeared now.

This type of system is very dependent for its fire safety on the integrity of the render and the proper fitment of protective shields of non-combustible material, especially around door and window openings and any protrusions. The expanded plastic may be "treated" to reduce its flammability and promote charring, so that it will tend not to promote a fire (and may be difficult to light), but if subjected to a fierce source (eg flames coming out of a fully-developed fire through the windows), from what I was able to see, they will still burn and produce really nasty toxic gases. The temperatures produced by a fully-developed fire in an apartment make "man holding blowtorch to insulation" look like a kitchen match in comparison. The inspections that were carried out on UK buildings after Grenfell revealed many examples of shoddy workmanship, where gaps were left between metal covers and the parts that they were supposed to be fixed to, and gaps filled with combustible material, missing fire-stops, wood frames used as supports for the various elements, etc etc. Once this type of system has been fitted, even well fitted, then of course it has to be properly maintained, and any modifications (eg when people fit external shutters or new windows frames, or ventilation flues etc) need to be properly installed to ensure that they don't provide a path for air and fire to get into the insulation. These subsequent modifications are frequently carried out by people who have absolutely no idea what the implications of their works could be. This is why we went for a system that had no combustible elements in it as it reduces/removes the risk of the effects of a maintenance or installation oversight or subsequent damage. Incidentally the rain screen that had been originally fitted to our building would withstand a blowtorch played on its aluminium surface for quite a while (we know because when we removed samples for testing by BRE, we had some material left over and our maintenance guys had a blowtorch, so inevitably we played with it), but as soon as the blowtorch touched an exposed edge (where the plastic core between the aluminium outer sheets was exposed), the sheet sample caught fire in a very impressive manner. Don't do this at home!