What Is Attic Rain and How Do I Prevent It?

Builder laying attic floorboard to prevent attic rain from occurring

The weather in Canada can be unpredictable. We can see days of frigid temperatures that swing to milder conditions within a week. The extreme changes in weather patterns can impact your home, and in some instances cause attic rain. But what is attic rain, and how do I prevent it from occurring?

Attic rain is a condition when warm moist air gets into the attic space and accumulates on the underside of your roof’s sheathing. It then freezes during the cold temperatures and when it melts, it may cause water damage on your celling and drywall. This is more common in homes that are less than 15 years old due to the overall air tightness when compared to older homes.


What Can Happen if Attic Rain is Not Dealt With?

Some people may not consider the consequences of accumulated moisture in the attic. If you do not act quickly, a fluctuation in weather may cause damage to your home. Over time, the freeze-thaw cycle can stain your ceilings, interior walls and window frames. It can also compromise your insulation and drywall and may lead to mould, mildew, fungus and bacteria.

Does my Home Insurance Cover Damage From Attic Rain?

Unfortunately, damage as a result of attic rain is not covered under some insurance companies’ policies. Be sure to review your policy or speak with your insurance agent to understand what is and isn’t covered under your policy.

How to Prevent Attic Rain?

Infrared Thermal Imaging Camera Pointing to Attic Access

Reducing the amount of moisture inside your home can reduce the risk of attic rain. Here are some possible options to consider exploring:

  • Humidity buildup in bathroom – Consider using the bathroom fans to help clearing humidity in the bathroom during and after showers.
  • Avoid using humidifiers on a high setting during colder months – Though humidifiers can help make a home more comfortable during the winter months, too much humidity may contribute to the build up of condensation.
  • Seal any drafty areas – While it’s been said that attic rain is caused when water molecules collect, freeze and condenses, to prevent these water molecules from collecting in certain crevasse, it’s important to ensure that these areas are sealed. Areas to check include ensuring attic hatches are airtight, openings in the celling’s drywall are covered and window frames are sealed. To help reduce unwanted airflow coming into the home, apply caulking around any fixtures that have not been adequately sealed.
  • Ensure that dryer, bathroom and hood fan vents are blowing outside, not into the attic space – Fan ducts can become disconnected or dislodged over time, allowing the hot, moist air to get caught in the attic, where it freezes. Be sure to speak with a contractor to ensure that your vents are moving air outside of the home.
  • Install a Heat Recovery Ventilator (HRVs) – HRVs can help to replace damp indoor air with dry outdoor air, which can reduce the risk of attic rain or the accumulation of moisture inside the home.

Many of these tips can be done by changing certain habits within your household. If you suspect that your home requires additional work, be sure to contact a reputable contractor to determine if your home is properly protected.

Disclaimer: This information has been provided for your convenience only and should not be construed as providing legal or insurance advice.