News at Historic Plaster Conservation Services - Notre Dame Cathedral in Ottawa

Notre Dame Cathedral in Ottawa

Nave ceiling, Notre Dame Cathedral in Ottawa. Notice the crockets on the ceiling rib nearest the top of the photo.
Click for larger photo. Historic Plaster Conservation Services (HPCS) has recently been appointed to undertake conservation activities at Notre Dame Cathedral in Ottawa on behalf of the Archdiocese of Ottawa. Our work will be part of a much larger restoration project under lead architect Sue Monk of E. J. Cuhaci & Associates, Architects. This Gothic Revival cathedral has undergone a complex evolution over the 160 years since the first phase of its construction began.
Our appointment was based on an extensive survey of plaster conditions that was carried out last fall. We are grateful for the generous participation of conservation consultant Martin Weaver and to Chris Borgal of UMA Engineering. Professor Ian S. Hodkinson confirmed our findings in an independent review.

At present HPCS has responsibility for the following:

The consolidation and strengthening of all of the ceiling plaster of the nave and sanctuary. Our team of (up to ten) technicians will carry out this work from within the attic space above the nave and sanctuary. Following this work, surface repairs of damaged areas, cleaning of the elaborate decorative paint schemes, and in some cases repainting will be done. The plaster, upon which all of this depends, will be sound and secure when we have completed this phase of the project.
Notre Dame Cathedral in Ottawa. Click for larger photo.

Notre Dame Cathedral in Ottawa. Close-up of crockets (now removed) and ribs at the ridge. Gold-coloured corner bracket is cast iron. Click for larger photo. The conservation of 18, elaborate, hollow, slip-cast, plaster crockets that decorate the plaster ceiling rib between the nave and sanctuary. These pieces, about the size of a large pizza and ten or so inches thick have very thin walls, as thin as 1/2 inch. Seven of them have been removed in an emergency intervention after the appearance of fresh cracking around their points of contact with the ceiling rib. These seven are presently undergoing study in our labs (or laboratory).

The development of a plan for the conservation of all other endangered plaster elements in the cathedral. This includes the intriguing problems associated with 38 hollow plaster columns that line the sanctuary. These columns are about 12" in diameter and 25 feet tall. They are made of plaster over a wood lath frame.
The laths are nailed in an overlapping fashion to rough circles of pine about 30" apart to make up the height of the columns. Capitols and bases are of cast plaster, sometimes hollow, and always fragile. Elaborate faux finishes of marble are applied to the surface. This surface is badly cracked and shows signs of compression strain and just about every other distress one might expect.

Typical cluster of plaster columns, Notre Dame Cathedral, Ottawa.Click for larger photo.

The development of a conservation plan for the approximately 3/4 mile of hollow plaster ribs that crisscross the ceiling. There are sixty ribs, each 70 feet long, on this ceiling. In all likelihood these ribs are fabricated in at least two, and more likely three different ways. A renovation in the later part of the last century extended the church and it is from this period that these large ribs date. We have to establish how the enlargement was carried out over the modest ribs that had been present prior to the renovation. Almost all of the ribs show distressing signs of cracks both along and across their longitudinal axis.
We will be posting news to this part of our site as work progresses. Bookmark it now and be kept up to date. The whole project is expected to take about three months.

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For further information, please contact:

Historic Plaster Conservation Services Limited
26 Barrett Street, Port Hope, Ontario, Canada L1A 1M7
Tel: 905-885-8764 Fax: 905-885-8330 E-mail: info@historicplaster.com

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Web site by Blue Cat Design.

Nave ceiling, Notre Dame Cathedral in Ottawa. Notice the crockets on the ceiling rib nearest the top of the photo. Click for larger photo.	Historic Plaster Conservation Services (HPCS) has recently been appointed to undertake conservation activities at Notre Dame Cathedral in Ottawa on behalf of the Archdiocese of Ottawa. Our work will be part of a much larger restoration project under lead architect Sue Monk of E. J. Cuhaci & Associates, Architects. This Gothic Revival cathedral has undergone a complex evolution over the 160 years since the first phase of its construction began. Our appointment was based on an extensive survey of plaster conditions that was carried out last fall. We are grateful for the generous participation of conservation consultant Martin Weaver and to Chris Borgal of UMA Engineering. Professor Ian S. Hodkinson confirmed our findings in an independent review.
At present HPCS has responsibility for the following:
The consolidation and strengthening of all of the ceiling plaster of the nave and sanctuary. Our team of (up to ten) technicians will carry out this work from within the attic space above the nave and sanctuary. Following this work, surface repairs of damaged areas, cleaning of the elaborate decorative paint schemes, and in some cases repainting will be done. The plaster, upon which all of this depends, will be sound and secure when we have completed this phase of the project.	Notre Dame Cathedral in Ottawa. Click for larger photo.
Notre Dame Cathedral in Ottawa. Close-up of crockets (now removed) and ribs at the ridge. Gold-coloured corner bracket is cast iron. Click for larger photo.	The conservation of 18, elaborate, hollow, slip-cast, plaster crockets that decorate the plaster ceiling rib between the nave and sanctuary. These pieces, about the size of a large pizza and ten or so inches thick have very thin walls, as thin as 1/2 inch. Seven of them have been removed in an emergency intervention after the appearance of fresh cracking around their points of contact with the ceiling rib. These seven are presently undergoing study in our labs (or laboratory).
The development of a plan for the conservation of all other endangered plaster elements in the cathedral. This includes the intriguing problems associated with 38 hollow plaster columns that line the sanctuary. These columns are about 12" in diameter and 25 feet tall. They are made of plaster over a wood lath frame. The laths are nailed in an overlapping fashion to rough circles of pine about 30" apart to make up the height of the columns. Capitols and bases are of cast plaster, sometimes hollow, and always fragile. Elaborate faux finishes of marble are applied to the surface. This surface is badly cracked and shows signs of compression strain and just about every other distress one might expect.	Typical cluster of plaster columns, Notre Dame Cathedral, Ottawa.Click for larger photo.
The development of a conservation plan for the approximately 3/4 mile of hollow plaster ribs that crisscross the ceiling. There are sixty ribs, each 70 feet long, on this ceiling. In all likelihood these ribs are fabricated in at least two, and more likely three different ways. A renovation in the later part of the last century extended the church and it is from this period that these large ribs date. We have to establish how the enlargement was carried out over the modest ribs that had been present prior to the renovation. Almost all of the ribs show distressing signs of cracks both along and across their longitudinal axis. We will be posting news to this part of our site as work progresses. Bookmark it now and be kept up to date. The whole project is expected to take about three months.