The £2.8m Lakanal House refurbishment project resulted in the installation of replacement materials with a worse degree of fire performance than the originals, the ongoing inquest has heard.
And confusion over responsibilities in the project team meant that neither the client (Southwark Council) nor the main contractor (Apollo) apparently sought building control approval for the works.
Last week, the inquest into the deaths of six people in the July 2009 fire heard that the poor fire resistance of the replacement panels beneath the windows – estimated by Dr David Crowder of BRE Global to be under five minutes – had contributed to the upward spread of the fire.
This week, the jury at Lambeth Town Hall heard detailed evidence from a number of individuals involved in the 2006-7 Decent Homes refurbishment.
Poor fire resistance of the panels below the windows contributed to the spread of the fire, the inquest heard
Apollo's contract surveyor/manager James Cousins gave evidence on Wednesday, followed by the client’s project manager Annabel Sidney of Southwark Building Design Services on Thursday.
Also questioned at Lambeth Town Hall this week were Thomas Campbell of window sub-contractor Symphony Windows and David Laing of Trespa, which supplied the boards that were used in the composite panels. Two witnesses also appeared for SAPA Building Systems, which wrote the performance specification for the replacement facade.
On Wednesday the inquest jury heard Apollo quantity surveyor James Cousins explain that, in the absence of any statement to the contrary, he assumed Lakanal would followed the pattern of previous Southwark Council contracts he had worked on, whereby Southwark Council Design Services was responsible for the design and building control approval.
The contract was not signed and executed until works were underway. However, the amended GE Works contract did in fact contain a clause committing Apollo to seek building control approval.
The inquest also heard about a late design change that resulted in the original specification of aluminium panels below the windows being changed to composite panels, after the client raised concerns that aluminium would not be robust enough.
Subsequent emails and conversations resulted in composite panels faced with two layers of 3mm standard non fire-retardant Trespa panels being installed below the windows, to match the Trespa panels that had already been specified for the balconies.
However, the inquest heard that the discussions focused on price and availability, and not fire performance.
Earlier, David Laing of Trespa had told the inquest that their product had been sourced via a distributor and the company was not originally aware of where on Lakanal House it would be used.
Symphony was responsible for the manufacture of the window assemblies including the panels, via a further sub-contractor. Some documentation it supplied referred to its work being covered by the FENSA self-certification scheme, but this in fact only applied to the glazing element, and not the solid panels beneath.
The inquest is expected to continue until 30 March.