Wednesday, November 1, 2017

Historic City Hall wrap: protecting workers and the building from the elements

As the temperatures plunge in Calgary this winter, the heritage rehabilitation of Historic City Hall continues full force ahead, regardless of ice, snow or sleet.

What is the purpose of the enclosure around Historic City Hall?

In May, 2017, the building was enclosed in a standard protective covering that contains the construction crew, equipment and materials. The enclosure provides overall project cost avoidances and plays a key role in the fulfillment of project timelines as the heavy duty wrap shields the workers from outdoor elements and keeps in heat, allowing us to work year round regardless of weather. In addition, this enclosure – which allows no water penetration – is vital in helping to protect the sandstone and exposed building components from the weather.

Inside the wrap, the crew working on Historic City Hall will remain warm throughout the winter. In order to ensure that building components don’t freeze – and that our mortar cures properly – the temperature inside the wrap is a minimum of 10 degrees Celsius, rising to about 20 degrees in the upper floors.

By protecting the workers and building from outdoor elements like snow, rain and extreme heat, we are able to work year round and avoid costly weather-related project delays. As well, enveloping the entire building at once as opposed to covering individual portions as work progresses is far more cost effective. The cost of the enclosure in its entirety – including materials, printing, and installation – was approximately $165,000 or $5.16 per square foot. This equals about $55 per day over the remaining three years that it will be in use.

Why is there imagery on the enclosure?

Imagery on protective enclosures is an industry standard for long term heritage rehabilitation projects, particularly when a building will be hidden from public view for years. Because Historic City Hall will literally be “under wraps” until 2020, we thought it fitting to use imagery that replicates the original appearance of City Hall. Given the Canada 150 celebrations that took place on Olympic Plaza and the Municipal Plaza this year, the imagery is also a fitting tribute to Canada’s historic anniversary.

Where else have they used images like this on historic buildings?

Examples of other heritage projects that are using or have used imagery on enclosures include: the Washington Monument, the U.S. Capitol Building and the U.S. Supreme Court Building (all in Washington D.C). This interesting article in Smithsonian Magazine describes some of those facades. New York’s Plaza Hotel had imagery on its enclosure during its renovations as did New York’s Whitney Museum of American Art. Like Calgary’s Historic City Hall, the Sydney Town Hall in Australia had a similar imaged fa├žade during its heritage rehabilitation. Philadelphia’s Independence Hall is another good example of imagery used during a historical restoration.

Both the scaffolding and the enclosure surrounding it are expected to remain in place until February, 2020, near the planned project conclusion of July, 2020. Please visit for project updates and historic photos and stories of Historic City Hall. 

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