The city is reminding Calgarians with flood-damaged homes to ensure they either heat the building this winter or have the water turned off to avoid further damage. 

Excess moisture in the ground from flooding in June has increased the risk of structural damage.

“An unheated property might allow moisture to freeze in and around the foundation, creating what is known as frost heaving,” said Marco Civitarese, Calgary's chief building inspector, in a release.

“Frost heaving can crack or even lift your foundation, causing structural damage that can leave owners with costly repairs in the spring.” 

Civitarese says if there isn't a working furnace, a safe alternative heat source is needed.

"We're going on a recommendation that you actually maintain some sort of heat in the basement and through the house," he said. 

"By doing so you alleviate the concerns and potential concerns for further expenses later in the year or during the winter season."

Frozen water line concerns

The city says not heating a house can also result in pipes breaking and flooding the property if water lines aren't turned off.

“It doesn’t take much for a water line inside a property to freeze if the furnace isn’t working,” said Chris Huston with Water Services in a release.  

“A frozen water line can quickly lead to a break that can cause extensive water damage to a property.” 

He said if the property cannot be heated then it is recommended to turn off the water inside the property using the main shut-off valve.

"And drain your taps, toilets and traps of water,” added Huston. “You should then contact 311 to arrange for a voluntary water service disconnection.”

The city says Red Cross is offering a winter emergency heat program to those who qualify, which includes the installation of a furnace and hot water tank. For more information contact the Canadian Red Cross at 1-866-696-6484.

It's believed that 80 to 100 homes and businesses are at risk of further damage if they are not heated.

Civitarese says 25 houses damaged by last June's flood have either been torn down or will soon be torn down.

Another 60 homeowners still have yet to decide whether to do extensive renovations or demolish their properties.

The city is also asking neighbours of unoccupied properties to contact 311.