'People think that it's the roof leaking': Experts voice concerns over growing reports of attic rain

Cody Sager and his colleagues have answered more than 30 distress calls over the past week from concerned Calgary residents.

The roofing technician, who works with Calgary Elite Roofing, says his team has been repeatedly dealing with complaints over what appears to be attic rain, a phenomenon that is often observed when the weather gets warmer after a cold spell.

"When it goes from –30 [or] –40 to plus five [degrees] in two days, that's when the issue presents itself and it will start by a small drip or some staining," Sager said.

"It could [even] be pouring water into the basement through the walls."

The issue can show up in several areas of the house, including ceilings, light fixtures and walls.

The culprit? Excess humidity.

"People think that it's the roof leaking. They don't understand that it's a condensation issue," Sager said before adding, "anytime it goes below –15 and stays there for a period of time, let's say for a week or so, and everybody's in the house boiling food and the kids are running around and playing … you got this extra humidity inside the home and it needs to go somewhere."

Excess humidity in the attic tends to freeze before eventually melting and leaking, causing condensation and issues that are hard to ignore.

Sager believes that it's important to be mindful of the temperatures outside and adjust humidity levels inside homes if needed to mitigate the problem.

"Sometimes you have to have a window or the curtains open to allow the moisture to burn off with the sun or have the bathroom door open while you're showering," Sager said.

Attic rain, according to the roofing technician, is often seen in newer homes that have been constructed over the last 20 years.

"I spoke with an engineer and asked him what his opinion was … he says the homes that we grew up in leak air from every corner of the building. So they don't have the condensation or the tight wrap that we have with newer homes today," Sager said.

Is it possible to stay on top of things and take preventative measures early on? It is doable, says Jaclyn St. Louis, a lead home inspector with Twenty20 Master Home Inspections.

"When it is getting extremely cold … that's the time that you really want to make sure your humidifier is down," St. Louis said.