Last week's cold snap has caused some problems for Airdrie homeowners in the form of attic rain.

Attic rain is the result of a buildup of moisture in the attic.

Chad Ferguson, General Manager of Beyond Foam Insulation says it's usually caused by an improperly installed vapour barrier, which is the poly underneath the loose fill insulation.

"When the home releases warm air from the upper floor into the attic, it condensates on the roof, just like it would when you have a shower and it condensates on a mirror," Ferguson explains. "In prolonged cold periods like we just went through, you can actually build up a significant amount of moisture or frost inside there. I've seen it as thick as 3.5 inches on an entire roof deck."

Ferguson says once the buildup starts to defrost, it can lead to several problems.

"You get that dripping down, leaking through the vapour barrier causing drywall damage, staining of the ceiling, possibly mould," says Ferguson. "When that water drips on your existing insulation, it packs it down and so you start losing R-value so therefore you're more at risk the next year or the next year after that depending on how much moisture packs down that insulation."

R-value measures how well insulation resists heat.

Ferguson says roof vents create a vacuum when warm air gets in and sucks the moisture out. However, roof vents can't keep up if the vapour barrier is poor.

He adds some homeowners try to add powered roof vents for larger suction, but that they can end up sucking more warm air out of the house and create more issues.

Attic rain is an ongoing problem that happens to people every year, according to Ferguson, who says he's seen an increase in cases in recent years. He is scheduled to be in 300-400 attics in the next month or two all with the same issue.

Anyone experiencing attic rain from the thaw of last week's cold snap can contact Beyond Foam for a free seven-point attic inspection.

 

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