What caused the water damage to the census forms? Flood? Or fire? Were they stored in the old Parliamentary Library in Ottawa before the advent of Canada’s National Archives which eventually became Library and Archives Canada (LAC)? I recalled from school history classes and from visits to Ottawa that the Library was saved when the Central Block of the Parliament Buildings burnt down in ---- . Suddenly I knew it was time to consult Wikipedia.
Okay, the fire took place in 1916 and at that time the library, completed in 1876, was saved because it was only accessible by a single corridor from the main building and that was blocked off by an iron door bolted in time by the chief librarian himself. Wikipedia doesn’t say whether firemen’s hoses might have done any damage to the roof.
Before the fire, however, was the flood. In 1888 a tornado removed the original slated roof, hence the building has had a copper roof ever since. There certainly could have been water damage at that time.
There was a fire in the Parliamentary Library in 1952, but I should think by that time that archives like past censuses would have been removed to the building on Wellington Street or wherever its predecessors were. It would not surprise me though if the 1952 fire set minds thinking as to how to preserve large amounts data on paper in some other way. The timeframe between then and the 1955 filming is not that great.
Protective wrapping such as we know it just wasn't available. The invention of plastic sheeting did not take place before World War 2. Tarpaulin wrapping would have been very costly. Were the censuses in cabinets? Who knows.
I also thought about the large part of the 1851 census (including all of Toronto) which is “lost”. What happened to it? Did it ever get to Ottawa? How was it transported to Ottawa? By cart or carriage, or by boat down Lake Ontario and up the Trent Canal? Did it get blown away in the tornado of 1888? Or lost track of in a move from one archive warehouse to another? The brain is wandering around. Must get back to sorting out where these people lived in 1861.