A leaked report from building standards experts BRE has provided the first proper expert analysis of the faults that contributed to the Grenfell tragedy last June.
We had been braced for some damning findings, but these were arguably worse than expected.
PVC windows with 15 cm gaps to the concrete structure acted as “fuel” rather than an obstacle to the fire.
Cavity barriers between the façade and the concrete structure were installed upside down, back to front and with gaps twice as wide as they were designed to seal in the event of fire.
The cladding and insulation were deemed “highly combustible”, while the manufacturer of some of the insulation could not be determined because it had no markings.
Perhaps the most galling finding of all was that the original building was designed and constructed to offer strong passive fire resistance and containment.
BRE said if the tower had not been refurbished in the way it was, there would have been “little opportunity for a fire in a flat of Grenfell Tower to spread to any neighbouring flats”.
In other words, no one had to die.
These findings from an interim report – BRE has only scratched the surface so far – point to failings at virtually every level.
From a construction point of view, the mystery insulation and apparently poor cavity barrier installation highlight two persistent problems in the industry: provenance and quality assurance.
An experienced quantity surveyor recently explained to me how a product can be changed from the original spec at virtually every link in the supply chain.
Value engineering can produce cheaper options, builders merchants can send “equivalent” products to site if they don’t stock the one ordered, while “architectural / design intent” can leave the spec open to interpretation.
In theory the compliance of the material should not change through these stages, but in practice the journey from design to installation offers many opportunities for material requirements to be misinterpreted or just plain missed.
There are some external checks on the quality of installation and materials required under building control, but these generally rely on looking at sections of the building at intermittent stages.
Ideally a client will have a clerk of works on site constantly, checking materials used and the quality of installation at every stage.
But we’re now seeing new technology emerge that can provide checks and records of material compliance and build quality.
Intelligent camera systems can record the construction process and provide a record of what was installed by who and when.
Distributed ledgers – blockchain technology – can securely record every design decision and purchase, while embedded ID tags can offer clear provenance of materials used.
If we combine this with BIM systems, then what is specified, procured and installed on a building need not be a mystery until a wall is opened up.
Instead we can have a reliable record of the structure that provides confidence and assurance from client to contractor and, most importantly of all, the occupants.
Clients, designers, consultants, contractors and specialists will all need to work with greater integration and transparency for this to work.
‘Construction trades on ambiguity’ is a phrase I’ve heard uttered, but the days of this old-fashioned approach look numbered.