Two award-winning plastering experts say much can be learned from the Apollo Theatre’s ceiling collapse
Initial findings, from an investigation conducted by Westminster City Council into the ceiling collapse at London’s Apollo Theatre in December last year, have revealed that aged hessian wadding was to blame for an accident that left 76 people injured.
According to two award-winning specialist plastering experts, with any luck the collapse will lead to improved facility management and vigilance by theatre staff and regular inspections by structural experts.
Ronnie Clifford, who founded Yorkshire-based Ornate Interiors in 1989 with brother Iain, has worked on hundreds of the nation’s historic buildings including theatres such as the Hammersmith Apollo, Stockport Plaza, Wolverhampton’s Grand Theatre, and St George’s Hall in Bradford (pictured).
He says: “This was a major tragedy that could have been averted with a bit more common sense and an acute awareness of just how sensitive and delicate some plasterwork ceiling constructions, dating back many decades, can be.
“This ceiling in question at the Apollo dated back to 1901, and the principal cause of the collapse was found to be the deterioration of plaster wads that were used to secure the ceiling. But there are a number of preventative measures that theatre owners can take to prevent this happening again.
“Apart from the required five yearly inspections, we recommend more frequent inspections to the roof and guttering, to prevent water ingress, and to ensure there is adequate ventilation at the back of the ceiling and no evidence of dry rot or other infestation.
But not all of the problems connected with historic ceilings can be discovered by just a visual inspection: Ronnie’s brother Iain says they may more intrusive investigations, especially when hessian wadding is used.
Iain says: “It’s been my observation, when ceilings have been fixed using plaster wads, that although wadding is very strong and secure, the hessian inside the wad will deteriorate over time while the plaster part of the wad remains strong, creating what we refer to as an empty eggshell.
“This is why, when requested to re-wad ceilings as part of a restoration process, we wrap tying wire around the fixing frame and through the lathed ribs that strengthens the casts. We then wad with plaster and hessian around the wire. This is done in case the wad fails at which point the tying wire remains in place ensuring a firm fix. In other words, we provide additional fixings and don’t rely on the hessian and plaster wads alone.
“Another cause of wad deterioration is other trades and theatre crew walking across the fixing frame standing on top of the wads to gain access. This causes the wads to weaken. The craftsmen of Ornate Interiors noticed this during their involvement in the recent restoration of ceilings at Hammersmith Apollo where the crew for Joe Cocker assembled their rigging over the Proscenium Arch causing damage to the historic mouldings.
“These guys have a job to do and need to do it quickly, so have no consideration as to the damage they may be causing.” says Iain. “We also have to bear in mind that todays’ theatre environment is so different from that of 100 years ago with the combination of vibration from the huge sound systems, modern heating systems, external traffic and subsidence. These are all factors that couldn’t possibly have been considered during the original planning and construction.”
Ronnie concludes by saying anyone involved in developing and maintaining such properties needs to be vigilant. He says: “It’s vital the public have the reassurances that inspections are being carried out and the necessary works are being undertaken to avoid further disasters.
It’s about educating as well as understanding the structure of historic buildings and the care required for their maintenance. So advice for owners and managers of these buildings is to ensure the contractors they employ are qualified to undertake the work. Site managers should seek relevant advice before starting work and replicate this advice for all site visitors and sub-contractors.”
Nor is it just about theatres.
“The Theatres Trust correctly identified many of the issues including the wide variations in plasterwork ceilings and the need for more rigorous assessments by plasterwork experts and structural engineers,” he says. “We therefore have to consider that these measures are not just exclusive to theatres but that they should also apply to the many other historic public buildings we have in the UK.”