Our Lady of the Assumption Church

Windsor, Ontario (1845)

Project Synopsis:
The church is undergoing a major multi-phase restoration. Phase One was completed in 2019 and included a new copper roof, heating system, and abatement work. Phase Two is the interior restoration which started in 2020 and is currently underway and includes stabilization and restoration of the vaulted plaster ceilings of the nave, aisles, and sanctuary. Historic Plaster Conservation Services is stabilizing the plaster with our unique Plaster Consolidation process.

In 2012 HPCS was retained by Alan Avis Architects (AAA) to inspect and comment on the condition of the elaborately decorated wood lath and plaster ceilings of the church. The plaster investigation was designed to address two issues. The first issue was public safety, and the second was to advise the church on issues related to the longer-term conservation of the plaster to facilitate the preservation and restoration of the high-quality elaborate painted and applied decoration on the ceilings.

Nave of Assumption Church.

HPCS concluded that the plaster did not pose any significant risk in the immediate future under the conditions of normal church use. The longer-term concern was that at 160 years of age, the ceiling might not survive the stress of a major construction program. Preventive maintenance to protect the ceiling plaster and its decorative finishes was thereby recommended at the beginning of the renewal program.

HPCS was invited back to the church to begin the first phase of the plaster consolidation work in mid-2020. One side aisle was stabilized successfully using HPCS’s line of Consolidants and Adhesives. Following consolidation, cosmetic repairs were made to the face and the decorative finish scheme was restored.

In 2021 we returned to the church to consolidate the second side aisle. As with the first aisle, the consolidation process started with thoroughly cleaning the back of the plaster, followed by hand-checking each plaster key and removing broken ones. Three applications of HPCS CO Primers and Consolidation Agent were sprayed on the back of the plaster. AD Premixed Lug and Key Replacement Adhesive was used to rebuild the missing keys. GR Non-Shrink Grout was used in the areas where the plaster had pulled away from the lath by more than five millimetres.

As Found condition in attic at Assumption Church. The plaster was covered in 160 years’ worth of debris and dust.
The final stage of consolidation: Applying AD Premixed key replacement adhesive to the cleaned and consolidated plaster.
The final stage of consolidation: Applying AD Premixed key replacement adhesive to the cleaned and consolidated plaster.

In 2023, HPCS returned to the Cathedral to consolidate the decorated nave ceiling. We treated about one-third of the nave ceiling using the same methodology and materials as in previous phases.

Historic Plaster Conservation Services