What is Attic Rain, and how to prevent it?

Anyone who has lived in Edmonton knows about the extreme temperature shifts from cold to warm and back again! Because these radical temperature shifts are routine, homeowners go to great lengths to protect their homes from moisture damage in the winter.


In this blog, we’ll run through everything you need to know about attic rain, including what it is, what causes it, and how you can prevent it on your property, among other things.

So What Is Attic Rain Exactly?

The term ‘attic rain’ is appropriate since the fundamental process of moisture forming is similar to the natural rain.


Here’s how it works: warm, moist air rises into the attic. Then, during a cold snap, that moisture freezes. When the weather gets warm again, the frozen water droplets melt to become liquid water droplets, which then drip internally. You could have trapped moisture in your attic all winter and not know about it until the temperatures rise, at which point you’ve got a problem.

close up of icicles hanging from eavestrough
icicles hanging from snow covered window

What Causes Attic Rain?

A few ingredients need to get mixed to produce attic rain. And unfortunately, many Edmonton homes have just the right quantities of all those ingredients! So, what’s at play? Let’s take a look.


Many homes can be humid, especially during the winter months. You’ll be cooking, baking, taking hot showers, and pumping your heating unit, which can lead to excessive humidity. Humidity rises due to its warmth, thus making its way to your attic.

Freezing Cold Temperatures

Having moisture in your attic can be problematic sometimes, but it’s especially challenging when a cold snap hits. Those water particles will form a sheet of ice at that point. It can happen quickly, especially in Edmonton, where cold snaps are routine during winter. 

Poor Ventilation

All homes produce humidity. But not all homes get attic rain. The difference? Some homes direct humidity away from the property. Homes with poor ventilation give moisture nowhere to go, so it ends up just sitting in the attic.

Poor Insulation and Gaps

You could have mould and other moisture-related issues if you don’t have adequate ventilation. But let’s stay focused on attic rain for now. That’ll be likely to happen when there’s a fluctuation in temperatures. Cold air will enter your home if your attic has poor insulation or draughty gaps.

Newer Homes May Be More Susceptible

There’s plenty to love about having a new home. But it’s not all positive. For instance, they’re more likely to have attic rain than older homes. Why? It all comes down to energy efficiency. You could argue that they’re too energy efficient. Newer homes are often exceptionally airtight, which is generally good for staying warm in your house but does mean that warm moisture has nowhere to go.

Some new homes have whole-house ventilation systems, which will help prevent attic rain — but if your home doesn’t have such a system or doesn’t work correctly, you’ll be more likely to have the problem.

The Potential Impact of Attic Rain

It’s easy to overlook the threat of attic rain. After all, how often are you going into your attic, anyway? However, it’s important to remember that everything is interconnected. What happens in your attic can — and likely will — impact other parts of your home, too.

Some of the consequences of attic rain include:


No one wants to live with black mould. Not only is it dangerous to human health, but it can be challenging to get rid of. If there’s untreated water in your attic, then mould can develop. However, it takes time to grow, so if you tackle the issue early on, you’ll be on the right path.

Electrical Damage

It’s no secret that water and electricity don’t go together well. If you have attic rain, you’ll have a flow of water beyond your control — and it could find its way to light fixtures and electrical appliances. If you notice attic rain (or any other water leak), switch off the electrical feed to that part of the home.


Water in the attic won’t stay in the attic forever; it often finds its way into other parts of your home, where it can cause significant damage.

Practical Tips for Avoiding Attic Rain

Don’t wait for disaster to strike! Take steps to avoid attic rain on your property. Some helpful tips include:

  • Turn down your humidifier: Keep it at 20 – 25% rather than closer to 50%.
  • Make sure your attic is well-ventilated: Look for any signs of frost. If you notice any, call in the professionals.
  • Run fans in moisture-heavy rooms: That means the bathroom and kitchen. 
  • Contact an expert: They’ll know what to do to prevent attic rain on your property.


Contact Dwight's Roofing Today

You can take some steps to reduce the presence of attic rain yourself. But getting the experts in will be essential if you continue to notice water marks inside your property. Here at Dwight’s Roofing, we have over thirty years of experience in roof repair, installation, and maintenance, which is another way of saying that whatever issue you have, we’re sure we’ll have seen it before!

We’re happy to provide a roof inspection and quote at your convenience. To get started, call us at 780-461-8995, email info@dwightsroofing.com, or fill out the contact form on the Contact page, and we’ll get back to you as soon as possible.