If you think your home is mold-free, you’re probably wrong.
As a fungus, mold is in soil and spreads to new locations by releasing spores into the air. It can travel through an open window or follow you inside through the front door.
But mold only becomes dangerous when it is able to attach itself to organic material and grow and spread with the right humid conditions, explains Joe Cascone, owner of Mold Pro Chicago, a mold prevention and removal company.
“Moisture allows the mold that’s already there to grow and colonize, and reproduce and spread,” Cascone says.
People's reactions to mold vary depending on individual predispositions to mold and the type of mold growth, from no symptoms to sore throat and itchy eyes, heightened asthma problems, skin rashes and in some cases autoimmune disease from prolonged exposure. Because medical issues can vary so greatly, it doesn't matter which type of mold may be growing or how you're feeling, all visible mold growth in your home should be removed and the source of moisture repaired to ensure growth does not occur again.
“Health effects are the first reasons to rid a building of mold. The second reason is the resale value and marketability of a property,” Cascone says. “Nobody wants to purchase a seller’s mold issue.”
Whether you’ve lived there for decades or you haven’t even closed on the place yet, evidence of mold can trigger dozens of questions. To avoid getting lost in the details, ask a few simple questions to help you get to the root of the cause, figure out how to fix the problem and how to move forward.
What's causing the mold to grow? It could be a leaky pipe, humid basement or a hurricane that flooded your entire first floor. The size of the problem is less important than your ability to repair the source of moisture.
“It’s imperative to stop further moisture intrusion,” Cascone says. Otherwise, the mold will just grow back.
Mold growth in a basement, attic or crawl space is relatively common, Cascone says, because residents don't see these areas often, and they can be very humid.
Mold’s potentially harmful qualities weren’t always a major concern. Larry Wasson, a certified home inspector and owner of Affiliated Inspectors in Chevy Chase, Maryland, says he wouldn’t be surprised to go into crawl spaces covered in mold as recently as 20 years ago.
“It wasn’t until at some point this medical research data hit the news" that mold could cause serious health problems, in addition to allergic reactions and heightened asthma symptoms, Wasson says.
An understanding of how mold grows in the home and the potential for adverse health effects has since changed the way people look at fungus, even if it's not causing you problems, you have to kill growing mold and reduce moisture levels to prevent its return.
Bigger disasters, such as hurricanes or a pipe burst, will likely require major remediation efforts, since surfaces exposed to moisture aren’t isolated. A flooded basement, for example, could see widespread mold growth.
Who should you talk to about it? To ensure you address any evidence of mold growth appropriately, it’s best to talk to a professional who specializes in inspecting homes and checking for mold – and be sure they’re an impartial source.
Charles Gallagher, an attorney specializing in toxic mold litigation in St. Petersburg, Florida, recommends selecting two separate companies to perform the inspection and remediation to ensure impartiality, and even more important, to make certain the inspection has merit.
“You want to make sure that you have two different sets of folks involved, as opposed to one person coming out who is a drive-by repair, handyman kind of service who doesn’t understand the scientific aspect of it,” Gallagher says.
If you haven't yet closed on a home and you find mold, it’s typically a good idea to hire your own professional to assess the situation to avoid having the wool pulled over your eyes by a desperate seller.
Some things to look out for: Phrases like “mildew” and “mold-like substance” are misleading. Mold and mildew are both fungi, and they can cause health problems. Wasson says that if it looks like mold or is described as a mold-like substance, consider it mold and have it removed.
“Nobody differentiates between mold and mildew – they both are just as risky as the other,” Wasson says.
How do you get rid of it? The spectrum of mold growth removal can range from a simple at-home cleaning to a heavy-duty remediation process that requires residents leave until conditions are safe enough to inhabit the home again. For spaces that are just a little too humid, a dehumidifier that's the right size will help to keep moisture levels in the air below 50 percent, which is the threshold for many types of mold to grow.
When Cascone inspects a home that doesn’t need remediation, he typically recommends mold-killing products that can be found at a local home improvement stores like Home Depot or Lowe's.
But contrary to popular belief, bleach is not an effective remedy. “It will just keep coming back, especially if it’s growing on the paper on the drywall,” Cascone says.
Sprays specifically designed to kill mold are more effective, and mold-killing primer can be used to seal the surface once the mold is removed. While simple at-home fixes and smaller remediation processes are typically resolved quickly, larger mold problems could take a few days to completely mitigate.
In the case of mold from leaks and water damage, you need to not only repair the source of water, but also remove affected surfaces, kill any fungi and treat anything you cannot remove, like a painted concrete wall in your basement, to prevent mold growth from returning.
Another way to reduce the chances of mold returning to the area is to get rid of its food source, and Cascone says one option is to ditch regular drywall for fiberglass drywall.
“Fiberglass is not consumable; it’s not edible for mold. Fungus only eats or consumes carbon-based materials or organic materials that used to be alive,” he says.
How do you make a deal when there’s mold? Any kind of major defect can break a deal or have a big impact on negotiations when buying a home, and mold is no exception.
“Mold is without question one of the most prevalent risks you can come up [against when] buying and owning a house,” Wasson says.
It’s not worth risking the potential health issues, and mold will simply continue to devalue your property until the problem becomes so rampant that the home is uninhabitable. "Nobody wants to purchase a seller's mold issue," Cascone says, adding that, "Attic mold almost never affects the indoor air quality in the living space, but it sure threatens real estate deals."
Regardless of whether you’re on the buying or selling end of the transaction, be sure you understand the laws about informing a purchasing party about home defects. “The law in Florida and in most states, generally, is that you have to disclose all known risks,” which includes evidence of mold in the home, Gallagher says. Providing the details of a previous inspection, mold lab test results or even simply stating that stains on a wall might be mold could be considered sufficient disclosure.
Evidence of mold will change the way sellers are able to negotiate, but it’s better than being found guilty of nondisclosure. How the buyer will want to proceed varies depending on the individual and where you live.
The buyer and seller can agree upon a reduction in the sale price, leaving the buyer to make repairs, and in Florida, for example, there is a state standard – 1.5 percent of the sale price – that the seller is expected to cover for needed repairs to the home, unless both parties agree it's not necessary.
The other option is to negotiate that the seller make repairs before closing or the buyer taking possession of the home, which Gallagher says he would personally prefer: “I’d rather have a seller make the remediation to it, and then when I take possession of the property, it be mold-free, or in pre-loss condition.”
She has appeared in media interviews across the U.S. including National Public Radio, WTOP (Washington, D.C.) and KOH (Reno, Nevada) and various print publications, as well as having served on panels discussing real estate development, city planning policy and homebuilding.
Previously, she served as a researcher of commercial real estate transactions and information, and is currently a member of the National Association of Real Estate Editors. Thorsby studied Political Science at the University of Michigan, where she also served as a news reporter and editor for the student newspaper The Michigan Daily. Follow her on Twitter or write to her at email@example.com.