4 Hidden Dangers Lurking in Your Attic

Danger No. 1: Rodents

Consider this: A typical female rat has about five litters per year. Each of those litters yields five to 15 baby rats. It takes each of those ratlings only four weeks to start having babies of their own. Mice are just as prolific. Conclusion: In the space of a year, a single pair of rodents can fill your attic with thousands more.

As their name suggests — rodere is Latin for “gnaw” — rodents spend a lot of time chewing on stuff. Insulation, wires, plastic pipes, cardboard boxes, wooden joists — all fair game for your average rattus rattus. If you hear the midnight pitter-patter of tiny rodent feet overheard, expect electrical, plumbing, and HVAC damage down the line — and possibly structural damage to your attic itself.

And, of course, what goes in must come out. Rat feces will eventually dry and turn to dust. That parasite-and-bacteria-ridden dust can easily get sucked into your ducts and make its way into your kitchen, bathrooms, and bedrooms. Disgusting? Revolting! But also very bad for your lungs.

What you should watch out for: Nighttime scampering noises in the walls and ceiling.

What you can do about it: Call an exterminator ASAP. If you go with a professional, it could be a one-time payment. If you go DIY, your home may become a rat-infested war zone for months to come.

Danger No. 2: Attic Fans

Attic fans, or whole-house fans, draw warm, humid air out of the house via the attic during the dog days of summer, cooling upper stories. Home inspectors and contractors are still on the fence about how energy efficient attic fans actually are. If you’re running an air conditioner, for example, your attic fan may be pulling your conditioned air out too. On the safety front, there’s one thing the experts agree on: Attic fans can sometimes lead to backdrafting.

To be clear, I don’t mean your attic-fan-cooled home is going to self-combust like in the Ron Howard movie. Backdrafting in this sense describes a condition where the flow of gas from a water heater or furnace reverses direction because of negative air pressure inside your home, pulling toxic carbon monoxide in its wake. If your home meets both of these criteria — gas water heater or furnace and attic fan — you could be exposing your family to unsafe CO levels.

That’s the worst possible scenario, but you may run into other issues with your attic fan too. One of the biggies? Poor roof-top installations can cause roof leaks, which your insurance may not cover. Our homeowners guide to roof coverage has the full story on that.

What you should watch out for: Check for negative air pressure if you’re running an attic fan. There’s a simple test: Open a window while your attic fan is on. If you can feel the air being sucked back into your home, you may have a problem.

What you can do about it: Upgrade your older fan to a newer solar-powered or turbine model. Install a water-leak sensor in your attic to catch early signs of water damage. (Here’s our complete guide to water-leak sensors.) And definitely install carbon monoxide detectors. We recommend CO sensors whether you have an attic fan or not.

Danger No. 3: Mold

If you’ve ever poked your head into the attic and gotten a whiff of what you assume must be an ancient mummy your spouse boxed up and forgot to tell you about, then you may have a mold problem.

You may be thinking, well, it’s just a little mold. I can’t even see it. What’s the big deal? I’ll keep the attic doors closed.

If it were only that simple! For one, a little mold always turns into a lot of mold unless you deal with it promptly. Two, mold can be toxic. Three, just like rodents, mold feeds on materials such as flooring, insulation, and wooden beams. It can destroy things.

Finally — and maybe worst of all — mold may look about as mobile as a grease puddle, but it doesn’t stay put. Mold spores travel through the air like animal dander or dust. When they get sucked into your HVAC ducts, their next stop is your lungs, potentially causing severe respiratory damage that’s tough to diagnose.

What you should watch out for: The main ingredient for mold in the attic is condensation. Besides dampness, you should also be on the lookout for a rotting vegetable smell that goes beyond the typical musty box smell we find in attics. If members of your family are suffering from chronic allergies, chest pain, or asthma, that may also be a sign you have a mold problem.2

Danger No. 4: Smelly Bottles of Paint and Other Toxic Liquids

We’re all guilty of it: We’re tidying up and just stuff the bottle of bleach under the counter. Or the bottle of Windex, paint thinner, or ant killer. The list goes on. Of course, we know better than that. We’re just leaving it there until we find the time to put it where it really belongs, away from the kids on a high shelf in the garage.

Except there it stays, the perfect lure for a curious toddler or 8-year-old going through their Mr. Wizard phase and turning anything in a tube, bottle, or can into an exotic — possibly toxic — concoction.

Storing toxic cleaning supplies on a low shelf in the mudroom where your kids can get to them is not a good idea, but stuffing those same toxic, possibly flammable liquids into your cramped attic that has little to no ventilation and builds up heat in the summer? That’s a really bad idea.

What you should watch out for: Any cleaning supplies or toxic or flammable chemicals, including paint and paint thinner, in your attic that you may have put there and forgotten about.

What you can do about it: Remove them immediately and transfer them to a ventilated space.

The Bottom Line

Any of us with an attic should be counting our lucky stars. We have a special place to store our Halloween costumes and all our mother-in-law’s weird Christmas gifts! Plus our HVAC units can stay safe and dry.

Like that other place in the house prone to all sorts of costly damage — the basements — attics need some TLC. Checking for mold and unwanted four-legged visitors and upgrading or overhauling out-of-date systems are not only desirable, but also necessary. And you have to act fast. The longer you let an attic issue go, the more dangerous it becomes.

Of course, your attic isn’t the only place you need to watch over. For further reading, check out our guides to lead paint dangers in the house and smart-home hazards. If you have little ones, don’t miss our breakdown of 11 hidden household dangers for kids.