What is Attic Rain and Why are Newer Homes More Susceptible to it? 

Have you ever seen tennis-ball shaped water stains on your ceiling? Is it frozen pipes? A leaky toilet?  You might be experiencing a phenomenon called ‘attic rain’.

Calgary homeowners have been reporting dripping in the attic and water spots on their ceilings. Home inspectors are predicting a rise in attic rain due to the rapid cooling and heating we experience in Alberta.


What exactly is attic rain?

Attic rain occurs when warm moisture accumulates in the attic, freezes during cold temperatures, then melts when the weather warms again. This see-saw in weather produces the perfect attic-crying conditions to damage your house. The kicker?  It usually affects newer homes because there’s less places for air to escape.


Here are 6 tips to help you avoid attic rain in your home:

1.     Check to see if your attic is well ventilated. Caulk around any fixtures or vents that have not been adequately sealed.

2.     Make sure your vents go directly outside and not to your attic. Check out this resource for sealing your attic:

3.     Turn down your humidifier. The ideal moisture level for your house is 30%-50%.

4.    Turn on your kitchen exhaust fan while cooking.

5.     Install a HRV (Heat Recovery Ventilator). HRVs replace damp indoor air with dry outdoor air.

6.    Contact your builder. Ultimately, your attic should already have a mechanism to deal with the air flow and moisture build up. If it wasn't included in your property, it may be a symptom of poor design. Check the attic before you invest in a home. 


What Causes Attic Rain?

Attic rain occurs when heat and moisture from everyday activities such as cooking and doing laundry leak into the attic. When temperatures are cold, the moisture turns into frost and can settle into layers up to eight inches thick. The longer the cold period lasts, the more frost can accumulate until warmer weather comes around or one of Alberta’s famous Chinook winds blows through.


How Can I Prevent Attic Rain?

Preventing attic rain is all about controlling the moisture inside of your home. Here are some tips for keeping moisture levels down.

·         Do not run a humidifier if your indoor humidity is between 30%-50%.

·         Turn on your oven hood exhaust fan while cooking.

·         Turn on your bathroom exhaust fan while showering or doing laundry.


Why Are More Homeowners Dealing with Attic Rain Lately?

Calgary  roofing contractors have noticed that part of the reason why attic rain is becoming more common is that it is more likely to occur in today’s newer and more energy-efficient homes. New construction homes in Calgary, Edmonton, and throughout Alberta are far more airtight and do a much better job at trapping moisture and warm air inside. This is why many new homes have a whole-house ventilation system which exchanges all of the air inside of the home with outside air.

If your home does not have this system or if you don’t run it often enough, then you could end up with attic rain.