field stone as building material My first encounter with field stone as a building material was at the site of the historic Lac La Biche Oblate Mission, established in 1853, 212 km north of Edmonton. We always knew that the original late nineteenth century building foundations were made from uncut field stones that would have been collected from the Mission’s fields adjacent to their location beside Lac La Biche. In 2012, I prepared a conservation plan for the entire Lac la Biche Mission site for a Parks Canada-funded conservation study. In the report, I noted that the church’s shallow stone foundations, rebuilt after a 1921 tornado, were severely out of alignment and had deteriorated after years of winter frost heave. Lac La Biche Mission is a designated and protected Provincial and National Historic Site. In consultation with a provincial heritage advisor, it was determined that the most appropriate form of conservation would be to completely restore the uncut stone foundation in situ , using the original stones and lime-based mortar materials, with a small amount of cement added to the lime mortar mix to increase durability. 3 As much as field and river boulders formed the earliest building foundations in the 1800s, by the 1900s the new settlers were looking for a more sophisticated use of field stone as a building material. The first Lac La Biche Mission Convent building, believed to have been constructed substantially from stone as determined from the rock piles at the site, had failed by the 1890s probably due to poor, or unstable, soil conditions. It was evident that the use of stone as a building material would require a solid concrete foundation to become a stable structural building component.
Lac La Biche Mission Archives
James Dow
from the top: the nineteenth century Lac La Biche Mission, founded by the Oblates of Mary Immaculate in 1855. Lac La Biche Church prior to restoration Testing the depth of the foundation wall and the soil it rests upon. The Lac La Biche Church foundation, before and after restoration
3 The repair and restoration work were completed in 2014 with the invaluable historic masonry expertise provided by Scorpio Masonry, Edmonton.
field images: David Murray
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on site review 48 :: building materials
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