Southwark Council has been told strengthening works must be carried out on the Ledbury Estate towers, or they could eventually become vulnerable to “exceptionally strong winds”.
A report by building surveyors Arup, published on Monday, detailed a catalogue of structural weaknesses found in the fourteen-storey blocks by Old Kent Road.
“To provide the buildings with sufficient resistance against disproportionate collapse, to meet current codified recommendations and best practice, structural strengthening measures are required,” the report said.
It recommended that concrete panels in the external and inner walls need reinforcing with steel, and that existing steel wall-ties need replacing.
Failure to do so in the “long term” could leave them unable to support the weight of concrete wall or floor panels on levels above, and therefore vulnerable to collapse, if accidents such as “exceptionally strong winds”, “vehicle impact” or “fire” occurred.
Fire safety issues with cracks in dozens of residents’ walls were discovered in June, after the Grenfell tower tragedy.
Arup’s previous investigations found in August that the towers could have collapsed if a kitchen gas explosion had happened at any point since they were built (between 1967-70) because they had never received essential strengthening works.
Although all gas heating was cut and has been replaced, the council now faces the choice of whether to pay for extensive works, or to demolish the towers and rebuild them.
Councillor Stephanie Cryan, cabinet member for housing, said the council had taken up Arup’s recommendation of “banning” residents from using bottled gas and oxygen cylinders.
She said: “We have been reminding residents not to use these [gas and oxygen] in weekly newsletters, and strengthening needs to happen in order to mitigate the risk of high winds, for example. We need to consider all these other factors in our options for, and risk assessments of, the building and that is what we will be doing with the help of the independent consultant we plan to appoint in the very near future.”
Arup’s report said the “intrusive” strengthening works needed on the four towers “will require local removal and reinstatement of plaster finishes, floor finishes and floor screeds, heating pipes, radiators, sanitary ware including baths and kitchens”.
Cllr Cryan added: “The next steps will be to appoint an independent consultant to look at the possibilities for the future of this estate. We hope that the resident project team will be involved in this appointment as well as helping to steer their work, before coming back to residents with options. Whatever those options are [to strengthen or demolish the blocks], we know that residents will have to move out, either temporarily or permanently. I know this will be hugely disruptive for every family who needs to move, I apologise for that disruption, and I thank everyone for their patience. I want to reassure residents that we will do our utmost to make the process as smooth as possible and with as much support as we can offer.”
The News understands that the council will most likely make the decision at a future Cabinet meeting, after an “options appraisal” is produced by the consultant.
Council leader Peter John had previously said the council would be “extremely unlikely” to be able to rebuild the estate “without some private sector cross-subsidy” due to the council’s limited spending and borrowing power.
Since July, all tenants have already been given Band One priority to bid for new homes.