Cheryl Cicco (licensed architect, water-damage/mold specialist) presents a short explainer on the top five causes of attic mold: (1) inadequate ventilation — mismatched or blocked soffit intake and ridge/mushroom exhaust, (2) HVAC/air-conditioning equipment or ducts located in unconditioned attics causing condensation and blocked condensate drains, (3) air leakage from the conditioned living space into the attic (warm moist air rising and condensing), (4) bathroom and dryer exhausts terminating in the attic or into soffits (often causing short-circuiting and moisture ingress), and (5) leaky roof penetrations/flashing. She gives practical advice: inspect and balance intake vs exhaust, avoid placing AC or ductwork in attics when possible, regularly service condensate drains and coils, air-seal the ceiling plane, and ensure exhausts terminate outdoors. The video also promotes her "Build a Safe Home" course and the website avoidingmold.com for more resources.
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Today we're going to talk about a list. The topic is attic mold or mold growing in attics. And I am Cheryl Cicco. I'm a licensed architect specializing in water damage and mold. Having me and my family debilitated by environmental aspects that were affecting our home, our many homes, actually. We have recovered and are doing well. And it's my mission to help other people do the same. So let's talk about mold in the attic. And there are five things that contribute to mold in the attic. So we're going to go through those quickly. Number one, inadequate ventilation. So most attics are ventilated and designed to be ventilated. There are. It is possible to do a great attic that is not ventilated, but it has to be designed that way. So I'm going to focus on lack of ventilation for those that should be ventilated. And if you see soffit vents, soffits is the underside of the overhang of the roof. That's usually where the air would come in. And then on the roof there's some. There's either mushroom vents, which looks like a metal upside down pan that allows air to get out, or there's a ridge vent, which is a raised section of the, the peak of the roof, which should allow air to get out. Know that the in and the out need to be matching as close as possible. And often that's not the case. Sometimes one or the other of those are blocked. Understand that you can't have out if you don't have in. So to have ventilation, there has to be air coming in and a place for air to go out. It's not just if you just went into a room and opened one window and, and nothing else opened in the house that you won't have ventilation. You'll have an open window. And if the wind is blowing in the right direction, you might have a breeze blowing in, but you won't have air moving through unless you have an in and an out. So that was number one ventilation. Number two is heating, air conditioning and ventilation ducts or air conditioning condensers in the attic. All of those things can lead to mold in the attic because they are. The attic is typically an unconditioned space and it's worse. Heating season isn't so bad if that's the case. But generally the air conditioning unit isn't used in the heating season. So in the heating season, heat is very dry. So we don't have an increase of moisture. In the cooling seasons, we usually have high humidity and we're Trying to blow cold air, which creates cold surfaces on the equipment that's being used to create the cold air. And when we have warm humid air, it can condensate on those systems that are in this attic that oftentimes can be well over 100 degrees, even over 150 degrees in a hot climate. So we often have those ducts being leaky. We have condensation that gets inside the ducts. So that is a big cause of mold and addicts. And so if you have that situation, which I never recommend if you're building new construction or avoid that, but if you have it, that's something that needs to be investigated. Heating air conditioning systems actually air conditioning systems have condensate drains which are taking the humidity out of the air. And those also get blocked and can lead to mold damage from overflow of those. Those drains that get blocked and they can get blocked by all kinds of things. So they need to be checked regularly. The coils need to be checked and cleaned regularly. And the whole system should be confirmed that it's air sealed the very, very tightly and insulated well. And if possible, I would never put an air conditioning unit in an attic or any ductwork if you can avoid it. Air leakage is number three. Air leakage would be just air from inside the space in the home that by natural convection currents rises up in the building and goes through the roof. If it gets trapped in the roof because of lack of ventilation or lots of reasons. In the winter, this could be warm humid air from people humidifying because they feel like they're more comfortable and hum. The air could be from bathrooms, it could be from cooking. Just the breath we breathe is humidity. And so that can go into the attic, hit a cold surface condensate and even have rain in the attic in the winter time, cold temperatures. So that's air leakage. We need to air seal the ceiling plane. The fourth is bath and dryer vent exhaust outlets. This is very frequent that I see these outlets ending up in the attic, often unsealed, never making it outside. And that brings moisture into the attic, which has no way to get out. And it's maybe one of the number one causes of mold in attics. The other concern would be if those exhaust fans are going out a soffit, which means they're going out the underside of something to blow down. Warm moist air only wants to rise. It will not be effective blowing down. And those softened vents are intake vents. So they're not intended to be drawing air in that somebody has hot and moist air blowing out right next door. So it's, it gets, the system gets short circuited and we end up. If we're trying to blow air out of soffit vent, it ends up coming right back in through an intake vent nearby. So bad idea. And then the fifth is a leaky roof. Yeah, that's an obvious one. If your roof is leaking, could be around any of those openings. Could be around exhaust fan openings. It could be around ventilation openings. It could be there's pipes that go through the roof for plumbing. Any of those things can leak. The flashing can leak. Caulk is not usually the solution. There should be a more manual solution of layering, of flashing and sealing. But that is another big reason why we have molden attics. Because the water gets into the attic and we don't see it in our living space for a long, long time. It collects there and it raises humidity. In addition to all those other things, I have a Build a Safe Home course. There's an intro and the full course that are available right now. And do come on and do live Q and A sessions for the people involved in the big course. And even if it's your own home, understanding how to build a safe home can be a great educational tool for you to understand what might have been done incorrectly in the home that you're currently in or in a home that you're looking to buy. So I hope this is helpful on mold and addicts. Check out my website, avoidingmold.com and I look forward to seeing you on the next video.
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