In every home, there is the potential for mold. Mold is everywhere. It’s outside, it’s indoors — and it may even be hiding in your walls. Mold can be dangerous, expensive to clean and repair, and spell serious trouble for your health and your home’s resale value.
What can you do to banish mold? Read our guide to learn why mold is so dangerous, how it forms, what you can do to clean it, and important steps you can take to prevent mold growth in your home.
Why Mold is Bad News for Your Home
Mold makes home owners nervous — and for good reason. Serious infestations, especially with highly toxic mold, can be a major health hazard and require expensive treatment for your home. But even a small amount of mold can be a problem for your health. With microscopic spores in the air, your family can experience allergic reactions, runny noses, and sneezing. It may also begin to smell bad.
While almost every home will get mold infestations, it’s important for home owners to stay on top of mold control and stop infestations before they grow to become a real problem.
Left unchecked, a minor mold infestation can quickly grow into a large one. And in addition to making you and your family sick, mold can cause rot and lead to damage of your home’s structure.
Mold typically aggravates symptoms for allergy and asthma sufferers. It can also lead to respiratory problems, irritation of the eyes, skin, nose, throat, and lungs, depression, and allergic reactions.
Mold is such a serious problem that many home buyers are wary of a house that has mold or has had mold in the past. It’s often tough to find, can be expensive to clean, and likes to come back once it’s been established in a home. Allowing mold to grow in your home unchecked spells trouble for your home’s resale value. And in the meantime, it can add up to serious and often expensive cleaning and repairs.
How Mold Forms in Your Home
Mold forms everywhere. It is indoors and outdoors and can easily enter your home through an open doorway or window. Mold also gets in through vents, HVAC systems, on your pets, clothing, shoes, and bags.
Mold likes to grow in areas with moisture. It can grow on your siding or decking outside, grow along shower grout lines, and even grow on your walls. Mold spores are everywhere in the air — and all they need to grow is a place to land, moisture, and a temperature between 40 and 100 degrees.
Mold does particularly well on ceiling tiles, wood products, paper products, and cardboard. Mold can also grow on carpet, upholstery, drywall, insulation, and wallpaper. There are a lot of places in your home where mold can thrive, especially in bathrooms an shady areas. Specifically, mold is most often caused by:
- Humidity: Humidity indoors can quickly lead to mold growth. Some mold spores only need a 55% humidity level to grow. High humidity feeds mold and makes any puddles or damp material take longer to dry out — which can further lead to mold.
- Leaky pipes and fixtures: Leaky pipes often go undetected for some time, typically hidding out of view inside a wall. When leaking fixtures or pipes are discovered, there is usually already mold growth established.
- Flooding: Mold only needs surfaces to be wet for 24 hours to start growing, so it’s easy for mold to thrive if your home has flooded. It’s especially easy if your drywall, carpet, or other porous surfaces have been affected, as they will take some time to dry out.
- Poor ventilation: A poorly ventilated home will allow moist air to stick around and leave a welcome mat of humidity out for mold spores. Wet surfaces will also dry out more slowly and lead to mold growth.
- Condensation: Condensation collects on cold surfaces in your home, such as metal pipes, concrete floors, windows, and even walls. Condensation can encourage mold growth with significant moisture.
- Roof leaks: Roof leaks can quickly lead to mold growth in attics — and as a spot that’s not frequented daily, mold can really flourish before it’s noticed.
- Damp basements: Basements are often cooler, allowing for more condensation. They also are often not well ventilated — and leaks in the home and at the foundation can all run down to the basement. Left neglected, mold can easily grow in basements.
- Wet clothes: Wet clothes left in a pile can lead to mold growth and encourage mold growth on floors and walls. Clothes should be dried in a dryer or outside on a line, not on indoor clothes lines.
- Water along home foundations: Water buildup in the yard and ground at your foundation can get into your home. Water should drain away from your house to prevent leaking and water damage.
Do You Have Mold? Signs of Mold in Your Home
Mold often grows quietly and is discovered suddenly. Many home owners don’t realize they have a mold problem until it’s already taken hold. Mold infestations may be discovered during renovations, when going up into an attic, or simply noticing a strange smell or soft drywall. Some home owners may not notice small mold growth and brush it off thinking it’s dirt or debris.
While mold can be easily hidden and sometimes tough to spot before it’s a serious problem, there are things you can be on the alert for to protect your home against mold growth. Keep an eye out for these signs of mold in your home:
- You see mold: This is the most obvious and troubling of mold signs. Physically seeing visible mold growth is an obvious sign of mold. Any time you notice dirt, soot, or discoloration of walls or other parts of your home, investigate further to determine its source. You may discover that it’s mold — and that there’s more growing than you can see.
- You smell a musty odor: Even if you can’t see mold, you may be able to smell it. A moldy or musty odor in your home suggests a high concentration of mold and should always be investigated.
- You have water leaks: If there’s water in your home, there’s probably mold, too. Busted or leaking pipes, overflowing fixtures, and other sources of water in your home are welcome mats for mold growth. If you have water in your home, be sure to follow up with an inspection for mold in the area.
- Paint is cracked or peeling: Paint on walls may crack, peel, discolor, or bulge due to moisture in a wall or in a wall cavity.
- You see lots of condensation in your home: Homes with high condensation on glass windows, metal pipes, and more are significantly more likely to have mold growth, as mold often grows where condensation collects. Look for condensation on windows, rusting indoor pipes, and other indications that your home has a high level of condensation that can invite mold growth.
- Parts of your home are wet, discolored, or rotting: Wet wood under floors, in crawl spaces, or drywall are signs that you probably have mold growth. Touching a wet wall almost certainly guarantees mold growth. And discoloration also suggests you have mold behind a wall or other part of your home’s structure.
- You have unexplained illnesses: Struggling with asthma symptoms, unusual stomach illnesses, and other unexplained ailments can point to a mold problem. Many mold sufferers experience headaches, trouble concentrating, dizziness, memory loss, and related symptoms.
- Your home has been flooded: If your home has flooded in the past, there’s a good chance mold started to grow. Look for mold in areas where flood water stayed the longest, such as a bottom floor or basement. Flooring and drywall will have the first signs of mold.
- You have a positive mold testing kit: Home improvement stores sell a mold testing kit — or you can hire a professional mold inspection company to take a look.
How to Fight Mold
Finding mold in your home doesn’t mean you have to throw in the towel and move out. Many homes with mold are able to be cleaned and remain a healthy and clean place to live. But mold is a serious problem and it requires serious cleaning — often with the help of professionals.
If you’re fighting mold, it’s important to take proper precautions, do a thorough job, and always follow up to make sure mold growth hasn’t returned to plague your home again.
Important Precautions to Take When Removing Mold
Flying mold spores in the air can be a serious threat to your health, and removing mold is a surefire way to disturb spores and spread them through the air. While you don’t need to prepare for a battle with basic infestations in bathrooms or on outdoor areas, you do need to be careful if you’re removing extensive mold, especially from areas like crawl spaces and drywall. Here’s how to protect yourself while you’re cleaning up extensive mold damage.
- Wear old clothes: Dress yourself in old clothes and shoes that can be easily thrown in the washer right after you’ve cleaned up — or better yet, thrown away altogether.
- Ventilate your work area: Use a box fan that you can easily dispose to ventilate your work area. Set it to blow air outside and be sure to cover the remaining window area with plywood or cardboard so that mold spores that have been blown outside will stay outside. When you’re done cleaning up, throw the fan away.
- Turn off your HVAC system: While you’re kicking up mold spores, the last thing you want to do is let them spread throughout your furnace or air conditioning system. As you’re doing mold removal work, be sure to turn off your HVAC system and cover ducts and other entry points to prevent mold spores from entering the system.
- Cover all areas with sheeting: Door openings, windows, floors, and more should be covered with thick plastic sheeting.
- Move furniture and items out of the room: All furniture and items should be removed from the room so that they don’t attract and reintroduce mold after you’ve removed it.
- Keep moldy areas wet: Moisture promotes mold growth, but it also helps to keep spores stuck to the surface you’re removing — and not in the air. Lightly spray moldy areas you’re working on to keep them under control.
- Wear a respirator: Protect your lungs from flying mold spores with a N-95 or P-100 respirator. It’s also a good idea to wear gloves and goggles.
- Double bag all moldy waste: Put moldy debris in thick garbage bags and double bag them. Tape up and wrap carpeting and other rolled moldy materials.
- Do not allow children or animals in the work area: While you’re cleaning up mold, make sure children and animals are not in the area.
- Don’t eat, drink, or smoke while cleaning: Avoid inadvertently consuming mold spores. Wait until you’ve changed and showered to eat, drink, smoke, or chew gum or tobacco.
Mold Fighting Tips
- Scrub moldy surfaces with a bleach and water solution: Create a solution of bleach, detergent (non ammonia), and water, then scrub firmly with a brush. Allow the solution to sit and penetrate the surface if it doesn’t come off with your initial scrubbing, then try again. Let the solution sit for a while to let it penetrate the surface. Then wipe the excess moisture and allow it to dry.
- Remove every piece of wall mold touches: If you have mold in your drywall, cut out as much as you need to — and maybe even a little more. You’ll probably have to remove a lot of drywall to get a good look at mold on your house structure, anyway. Just be sure to cut a small hole to locate wires first, then turn off power to the outlets before cutting.
- Remove and treat studs and sheathing if needed: Mold and moisture may have set in on studs and sheathing in your walls. If possible, remove and replace any of these pieces that are damaged. If removal is not possible, clean the wood, allow it to dry, and treat it with wood preservative. You’ll also need to add pressure treated wood to support the weakened structural pieces.
- Clean up debris with a wet/dry vac: Vacuum up small debris with a wet/dry vac. When you’re done, you’ll need to clean the vacuum, washing out the tank, hose, and attachments with a bleach and water solution. You will also need to dispose of the filter.
- Dust, vacuum, and mop the room: Give the rest of the room a thorough cleaning to catch stray mold spores. Vacuum, dust, and mop to make sure you catch as much as possible.
- Use a dehumidifier and new fans to dry out cleaned areas: Give your newly cleaned areas a chance to dry out. Set up a dehumidifier and a new fan. Leave them running for a few days and check for mold again before removing them.
- Seal surfaces: Seal wood surfaces with a shellac and paint wall surfaces with a paint that contains mildewcide. In the bathroom, apply a grout sealer to tile joints.
When to Get Help Fighting Mold
As a general rule, small mold infestations can be handled by home owners. But an area more than 10 square feet in size requires professional cleaning.
A minor mold problem can be tackled easily with household cleaning products. However, if you have a large infestation, you could suffer serious health effects if you try to clean it up without taking the proper precautions. This is especially true if you suffer from allergies or have a weakened immune system.
Everyday mold occurs in bathrooms, around sinks, along exterior door thresholds, and in damp basements. These mold problems can typically be handled with a good cleaning.
More serious problem mold grows on drywall and in structural pieces including studs and sub flooring. Serious problem mold is typically best handled by professional mold remediation companies.
Of course, some types of mold are highly toxic and require professional help regardless of the size of infestation. If you experience an allergic reaction to mold, or you’ve been told that the mold in your home is toxic, don’t hesitate to get professional help for your mold problem.
A professional can protect your home and your health by taking rigorous protective measures. They are experts in removing and containing mold and can help you not only control your current mold problem, but discourage it from coming back in the future.
But be careful to watch out for scams. Many scam artists will come into an area affected by flooding and storms, engaging in price gouging and even in outright theft. If you’re going to get help from a contractor or mold removal company, be on the alert and look for signs of shady dealings.
When hiring help for mold removal, look for a company that has a proven track record. Always find out if they’re licensed and insured (they should be). And of course, always get multiple bids so you have a basis of comparison. Don’t be alarmed if they can’t nail down an exact estimate due to the nature of the work, but be sure that you at least get a ballpark figure. Mold removal is not cheap: most home owners spend between $1,135 to $3,182. But it is worth it to get professional help when it’s needed.
How to Prevent Mold
Fighting mold is only half the battle. To truly rid your home of mold, you’ll need to take steps to make sure it never comes back again — or never introduces itself to your home at all. Prevention is the best way to stop mold in its tracks. There are simple steps you can take to help prevent mold and help protect your home against the danger of mold.
- Control moisture in your home: Mold thrives in moist environments. This can mean your bathroom or kitchen, but it can also mean bedrooms or living rooms if you live in a humid area. Turn on exhaust fans where steam and moisture build up. Open a window while you take a shower or do the dishes. Consider investing in a dehumidifier, especially in areas where your home tends to attract moisture.
- Immediately repair roof leaks: Roof leaks are a common cause of mold infestations, especially in attics. Have your roof inspected regularly and repair roof damage immediately. Otherwise, leaks and mold growth can spread unnoticed for months and even years.
- Paint wet areas with mildewcide: Keep surface mold out of wet rooms including your bathroom and shady areas outdoors. When painting, find out if the paint you’re using already contains mildewcide. If not, you can add it to the can.
- Use caulk around all water fixtures: In your sink, bathroom shower, and any other wet area, everything should be sealed up tightly with caulk.
- Check regularly for leaks: Leaks can happen anywhere and leave your home vulnerable to mold growth. Keep an eye on crawlspaces, in your attic and basement, and anywhere you suspect a problem with leaky plumbing, like an upstairs toilet or bathtub that’s not completely sealed or that may have overflowed. Identifying the source of leaks early on, treating them, and removing the mold can help you stop a serious mold infestation.
- Clean out your gutters regularly: Gutters filled with leaves and other debris don’t drain quickly — and standing water can lead to leaks and rot that can introduce mold into your home.
- Give your attic good ventilation: Right under your roof, your attic is part of your home’s first line of defense against moisture. Make sure air is able to flow freely through your attic so that any moisture that’s introduced can dry out easily.
- Caulk your windows: Be sure your window caulking is tight, as rain and other moisture can creep in.
- Change air filters regularly: Remove dust and mold from your home by getting a new air filter about every three months.
- Drain water away from your foundation: If you have bad foundation drainage, your basement can become a harbor for mold spores. Make sure you’re keeping water away from your foundation using gutters and installing a drain if necessary.
- Open windows and doors for ventilation: Whenever possible, open your windows and doors to ventilate your home and allow moisture to dry out.
- Clean spills quickly: Spilled liquids, water leaks, and small floods should be cleaned up quickly from floors, especially carpet. Carpet can hold moisture and take a long time to dry out, fostering mold growth.
- Clean drip pans: Dump water out of drip pans under your air conditioner and refrigerator.
- Don’t allow clothes to sit wet: Mold can quickly grow on a wet pile of clothes. And air drying wet clothes indoors can add moisture to your home, attracting mold growth. Clothes should be dried in a dryer with an exhaust vent that goes outside or on an outdoor line.
- Replace shower curtains with mildew: Shower curtains with mildew can encourage mold growth. Wash them in your washer with bleach or simply replace them.
- Dust and vacuum often: Dirt and grime are food for mold, so keeping your home clean can discourage growth. Dust and vacuum often. Look for a HEPA filtered vacuum cleaner.
- Let natural light in: Don’t give mold a dark place to grow. Even if you can’t open your windows, opening curtains to allow sunshine inside can reduce mold growth.