Built in the early 20th century, St. Joseph Parish is a local and regional historic landmark building that was recently designated under the Ontario Heritage Act. The Church is one of the most distinctive links to the francophone past of the community and is one of the very few venues in southern Ontario where mass can still be heard in French. The building is also widely admired for its elaborate interior decoration, including 17 highly detailed murals painted on the beautiful plaster-on-wood-lath vaulted ceiling. In short, St. Joseph Parish has extraordinary aesthetic and cultural value worthy of long-term preservation.
In 2012 the Parish commissioned a detailed study of the plaster ceilings to determine their condition. The study (conducted by Classical Restoration and Design) examined the condition of lugs and keys at the back of the plaster and found that between 40-45% of the keys had failed. A plaster ceiling is supported solely by its lugs and keys. When keys begin to fail the strength of the plaster system is compromised. In this case the study findings presented a serious safety issue for the Parish.
Based on the results of the assessment, HPCS was asked to conduct a trial plaster consolidation procedure involving treatment mock-ups on sections of the plaster ceiling at St. Joseph. HPCS has been effectively consolidating plaster ceilings of this type in heritage buildings for more than 30 years.
The purpose of conducting these treatment mock-ups was to demonstrate the HPCS method of making the overhead plaster safe. Consolidation and re-attachment of plaster on wood lath from the attic side of the ceiling is the state-of-the-art and most economical method of choice in historic buildings, especially where decorative finishes are at risk if plaster fails. Most importantly, the treatment extends the service life of plaster indefinitely.
The trial was a complete success. HPCS assisted the Lead Consultant on the project, Allan Avis Architects (AAA), with the design of the specifications for the plaster consolidation as well as the restoration of other plaster elements. Subsequently we worked with AAA to oversee the plaster consolidation work. In 2016 Allan Avis Architects and their team were awarded the James D. Strachan Award for Craftsmanship from the Architectural Conservancy of Ontario for the successful project.