Attic Rain: What It Is and How to Prevent It

If you live in a region that experiences harsh winters, you may have to deal with attic rain. Attic rain occurs when the outside temperature fluctuations and airflow issues cause moisture to accumulate underneath your home roof.

The trapped moisture may seep into your home causing water damage while affecting your home value.

What is attic rain?
Attic rain happens when the warm, moist air inside your house rises and condenses after coming in contact with the cold roof. This causes water droplets to appear on the inside of the roof, which then start to ‘rain’ down, causing mildew formation and structural water damage.

What are the causes of attic rain? 

The causes of attic rain may include:

●       Extreme temperature fluctuations: Rapid temperature changes can cause condensation when the warm home air touches the colder roof;

●       Poor ventilation: A poorly ventilated attic can trap moisture aggravating the issue. Also, heavy snowfall can block the house's ventilation system disrupting air circulation;

●       High humidity: Humid conditions mean more moisture in the air which gets trapped in the attic because of poor air circulation;

●       Structural issues: Houses with cracks and gaps cause warm air to gather in such places which condenses and causes attic rain;

●       Inadequate insulation: Poor insulation can trap warm air in the attic leading to attic rain.

What are the signs of attic rain?

Signs that your home has an attic rain problem include:

●       Mildew smell: You may experience a musty, unpleasant odor from the attic;

●       Water stains: Brown or yellow water stains are visible on the ceiling or walls;

●       Damp insulation: The home insulation can feel wet to the touch.

Untreated attic rain can have long-term consequences like:

●       Structural damage to the roof: The trapped moisture can weaken or damage the roof;

●       Reduced energy efficiency: Wet insulation will raise your home heating costs;

●       Mold growth: Excess moisture can cause mold growth.

How to Prevent Attic Rain
Attic rain can be prevented by:

Improving attic ventilation:
Keep your attic well-ventilated by:

●       Installing an attic fan for better air circulation. A smart attic fan can control the humidity in the attic reducing mold and mildew growth;

●       Using both intake and exhaust fans.

Identifying and sealing air leaks:
Identify air leaks and use caulk or spray foam to seal the gaps preventing warm air from escaping.

Controlling humidity:

Install a whole-home humidifier and dehumidifier to your HVAC system to control home humidity.