Winter 2024 Lesson Plan
Moisture Troubles in the Attic Can Cause Unhealthy Air Inside the House
Because the attic is not a section of our home we go into very often, it’s generally not on our minds. Here’s something that should be on our minds: The quality of the air inside our attics can affect the quality of the air we’re breathing in our living space. In the winter, a contributing trigger to problems in the attic is moisture.
Every day the average family of 4 generates between 2 to 4 gallons of water vapor through activities such as cooking, cleaning, showering, laundry, breathing and perspiration, etc. (Source: Moisture Control in Buildings, Heinz R. Trechel). This water vapor is attracted to a cooler, dryer place: the attic in the colder months. Once in the attic, a balanced system of intake vents (installed in the soffit/overhang or low on the roof’s edge) and exhaust vents (at or near the peak of the roof) helps remove this moisture safely to the outdoors before it becomes a problem. But, if the water vapor lingers or worse, never exits the attic, due to incorrect or insufficient attic ventilation (or other causes of excessive moisture such as incorrect bath fan ductwork installation) it can lead to mold and mildew.
Photos are courtesy of Tracy Pionek, True North Roofing, Cottage Grove, MN. Pictures show signs of moisture problems inside the attic on the underside of the roof deck as well as the nails.
Mold and mildew in the attic can go unseen for a long time before it catches the homeowner’s attention. It is the mold and mildew in the attic that can affect the air in the living space.
“We typically see this each winter here in Minnesota because we get lovely ice dams on our roofs. It is those ice dams that gets the homeowners’ attention and then they contact us,” says Tracy Pionek, True North Roofing, in Cottage Grove, MN, who talked with Air Vent about this in a podcast episode. “Once we are onsite, we do an attic inspection. What we often find right away is rusty nails through the underside of the roof deck telling us there is excessive moisture in this attic. Next, we see wet attic insulation. Two common examples of too much moisture inside the attic.
“Sometimes we receive phone calls about a leaking attic vent. But when we arrive and check the attic there is no leak at all. Instead, it’s too much moisture inside the attic that condenses and appears to be a leak. In reality, instead of it being a leaking vent it’s the case of not enough vents to begin with. This is always tricky to explain to a homeowner. They think it’s a leak through the roof. We explain it is condensation due to moisture not being removed correctly through attic vents.” Pionek says.
Homeowners should check the attic a few times during the year to see if anything is odd or wrong. Is there mold on the underside of the roof deck? Is the attic insulation wet, damp or darkened? If so, call a roofing professional for further investigation. If it’s not easy for homeowners to go into the attic maybe they can ask someone to help. Roofing contractors across North America should include at attic inspection during every roofing project when it’s safe and practical to do so.
Mold inside the attic can lead to living space air quality problems if left unchecked. Another Air Vent podcast guest, Jerry Becker, Roof Life of Oregon, in Tigard, Oregon, shared an example where mold in the attic was doing just that. The homeowner was using an oxygen apparatus that was with her everywhere she went inside the house, Becker noticed. She told him doctors never were able to diagnose why the apparatus was needed in the first place. During the total roof replacement and attic ventilation fix, Becker noticed mold, mildew, and a soaked roof deck from excessive moisture. One year after the complete roof fix, the homeowner telephoned Becker asking him to swing by. When he did, the homeowner wanted to show Becker she was no longer dependent on the oxygen apparatus to breathe normally in the house.
“We work on a lot of homes in Minneapolis and St. Paul that are very old,” says Pionek. “Some of those homeowners chalk up the musty smell that is apparent inside the living space as the result of it being an old home. I try to explain that possibly the stagnant air up in the attic is contributing to the issue. If we can remove that air through proper attic ventilation it might improve the situation in the attic and inside the living space.”
Listen to the podcast episode “The Air in Our Attic Affects the Air in Our Living Space”
Or catchup on a similar conversation,
Listen to the podcast episode “Fighting Wintertime Moisture”
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