In September, the museum was forced to close after maintenance workers discovered a leak in the roof that had spread to the building's south wall. Subsequent tests revealed high levels of airborne mould.
But an email sent to Canadian Heritage staff on Sept. 18 by the museum's president and CEO, Alex Benay — and obtained by CBC News after an access to information request — revealed the extent of the damage was greater than previously known.
Among the revelations were that the museum's roof is sagging in two locations and is "now officially collapsing" and that white powder is escaping from the ceiling, forcing anyone inside to "have to operate as though there is now asbestos and mould in the air."
The maximum snow load of the roof has also been reduced from about 45 cm to about 20 to 25 cm.
"The time for band-aid solutions has long gone and has frankly led us to where we all are today," Benay wrote in the email.
$80.5M cost to upgrade museum for 2017
Two weeks ago Canadian Heritage Minister Shelly Glover announced $80.5 million in funding to cover the costs of a new roof, an upgraded facade, updates to the exhibit space and a retrofit of the building to meet updated fire and earthquake-resistance codes.
The museum was expected to reopen in 2015, but after Glover's announcement the date was pushed to 2017, in time for the museum's 50th anniversary and Canada's 150th birthday celebrations.
Critics are questioning whether the plan to retrofit the building will be wasted on an old and dangerous building.
"We knew about the mould, but the fact that the roof was collapsing is obviously something that should be of concern for everyone," said Paul Dewar, the NDP MP for Ottawa Centre.
"I'm just glad that the roof didn't collapse when there were people there. You know, this is a place for families, for young people, for kids."
Viability of building questioned
Mauril Belanger, the Liberal MP for Ottawa-Vanier, said the government should revisit its plans given the extent and seriousness of the building's issues.
"I think it will cause people to question the decision that's been made," said Belanger.
Ottawa mayor Jim Watson had previously suggested the museum might better serve the city if it was moved from its current location at 1867 St Laurent Blvd. to a more central location, such as downtown or in the parcel of land near the Canadian War Museum at Lebreton Flats.
Watson said Tuesday he's concerned by the news of the current building's condition.
"Obviously these latest revelations are concerning. Public safety has to be number one," Watson said.
Royal Galipeau, the Conservative MP for Ottawa Orleans, has previously supported the plan to retrofit the existing building.
When asked Tuesday after question period, Galipeau did not comment on the condition of the building.
"Stay tuned," Galipeau said. "2017 will be a beautiful party and the museum of science and technology will be part of it."
Cost of new museum pegged at $250-375M
The cost of a new museum would range from $250 million to $375 million, according to internal museum documents.
Belanger said a new facility could allow more artifacts to be on display.
"I think that Canadians, generally, would be more willing for the government to invest a larger sum of money," he said.
Correction : An earlier version of this story incorrectly stated the museum was in the Ottawa neighbourhood of Orleans. It is located at St. Laurent Boulevard and Smyth Road.(Dec 03, 2014 8:59 AM)