When part of the ceiling of the Apollo Theatre in London collapsed in December during an evening performance, the falling debris caused a number of injuries but no fatalities. On Monday, the cause of the collapse was determined to be old material that had deteriorated, according to reports in the British press.
The main cause was the deterioration of "wadding ties" that supported the ceiling, which is believed to have been in place since the Apollo's construction in 1901, the BBC reported, citing a statement from the Westminster City Council.
The wadding ties are made of plaster of Paris and hessian, a cloth-like material, and are used to hold the ceiling in place.
This week, the Apollo is scheduled to reopen for the first time since the Dec. 19 incident. The theater will be the home of the play "Let the Right One In," based on the popular Swedish novel by John Ajvide Lindqvist that was turned into a movie in 2008.
At the time of the collapse, the Apollo was the home of another literary adaptation, the National Theatre's West End production of "The Curious Incident of the Dog in the Night-time." The production was suspended after the collapse and is relocating to London's Gielgud Theatre, where it is scheduled to reopen in June.
Aging theaters are a problem on London's West End, where many of the famous venues were constructed before World War II.