Toronto, Ontario (1907)
About the Building:
One of Toronto’s premier concert and speaking venues, Convocation Hall is a domed rotunda and the centerpiece building on the grounds of the University of Toronto’s downtown campus. Designed by renowned architects, Frank Darling and John A. Pearson, the building was inspired by the grand theatre of the Sorbonne and the Sheldonian Theatre at Oxford.
Treating Expanded Metal Lath and Plaster – Did It Actually Improve the Acoustics?
The ceiling is cementitious plaster with a gypsum finish applied over expanded metal lath. Persistent water infiltration had caused serious failure with pieces of plaster having fallen from time to time. Because it is a heavily used public assembly building, the prudent temporary fix was to install a netting – ugly but not uncommon – under the entire ceiling to catch any falling plaster.
In the year 2000, Historic Plaster Conservation Services was retained to study the problem and develop a long term solution to the deteriorating situation. The netting was appallingly unattractive and everyone wanted the problem addressed.
Our assessment led to the development of a special formula of consolidant, designed for deep penetration into cementitious plaster. The consolidation treatment was successfully applied and the safety netting was removed. Ordinary repairs were done to the interior surface and the whole place was tastefully painted. There have been no issues or incidents with the ceiling since. Some music aficionados commented that the acoustics in this famous hall improved after the ceiling was treated.
A similar situation currently exists at another renowned concert venue in Toronto – Massey Hall – where a temporary netting fix has been in place since the 1950s.