Two award-winning plastering professionals think much may be learned from the Apollo Theatre’s ceiling collapse
Initial findings, from an investigation done by Westminster City Council into the roof fall at London’s Apollo Theatre in December last year, have found that ageing 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 fall will lead to greater facilities management and vigilance by theatre employees and regular inspections by structural experts.
Ronnie Clifford, who started 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 (shown) (pictured).
“This was a major tragedy that could have been avoided 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,” he says.
“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. A variety of preventative actions, on the other hand, may be taken by theatre owners to keep this from 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 difficulties related with old ceilings can be identified by only a visual inspection: Ronnie’s brother Iain believes they may need intrusive inspections, especially when hessian wadding is utilised.
A hollow eggshell is the result, according to Iain, of ceilings secured using plaster wads rather than nails or screws. Plaster wads are incredibly strong and secure, but I have found that the hessian inside them degrades over time while the plaster element of the wad remains robust.
“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 time the tying wire stays in place ensuring a firm fix. To put it another way, we don’t rely solely on the hessian and plaster wads.
“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 observed this during their involvement in the recent restoration of ceilings at Hammersmith Apollo where the team for Joe Cocker assembled their rigging over the Proscenium Arch causing damage to the ancient mouldings.
Because of their urgency, these men don’t care about the potential harm they’re doing to the environment, according to Iain. For one thing, the current theatre environment is very different from that of a century ago due to the mix of vibration from large sound systems, contemporary heating devices and outside movement as well as subsidence.” All of these things were not taken into account during the initial design and construction.
Ronnie finishes by noting anyone involved in constructing and maintaining such properties needs to be attentive. For him, the public needs to know that inspections are being conducted and that the necessary repairs are being made in order to prevent any more tragedies.
It’s about teaching as well as understanding the structure of historic structures and the care required for their maintenance. As a result, building owners and managers should take care to hire only licenced contractors. Site managers should get necessary guidance before starting work and replicate this advise for all site visitors and sub-contractors.”
Nor is it just about theatre.
“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.”