Wood is a staple element of the majority of homes across the country. According to the National Association of Home Builders, over 90% of homes are constructed with this material. As a less expensive and flexible building option, it can be a great asset to any home, from the foundation to the finishings. While an incredibly versatile building material, there is one issue that many homeowners face: mold on wood.
New homes, older homes, and renovated homes all have the potential for this issue to pop up. Just think of all the wood that’s inside the average home! Each time a beam, floorboard, or windowsill is installed, an opportunity for that fungus among us to grow is created.
That’s why taking steps to safeguard our homes from mold on wood is so important. No one wants to hang out in a toxic indoor environment that negatively impacts their health.
Here’s what you need to know to remove mold on wood and how to prevent it from occurring in the first place.
Why Does Mold on Wood Occur?
Understanding how mold on wood occurs makes prevention infinitely easier. If you know why it happens, you’ll be better prepared to reduce the situations that allow it to occur.
But first, a little about that fungus among us.
There are over 100,000 species of mold identified so far, and they exist all over the world. Each species reproduces by creating and releasing microscopic spores into the surrounding environment.¹’² If these non-living spores stumble onto a surface with the right elements needed for growth, they’ll put down roots called hyphae and colonize the surface.
Their ability to grow roots is one of the main reasons why dealing with mold on wood properly is so important.
Thanks to their hardy nature, most species of mold only need two elements to transition into a living colony.³
These two elements are:
- A food source
- A water source
If these are present for 24–48 hours, that spore will settle down for the long run and start up the reproductive cycle.
Back to Mold on Wood
Wood surfaces can offer the perfect conditions for growth.
When it comes to a food source, the wood itself is made up of organic matter. That essentially means that the entire material is an edible buffet. Add in all of the other organic particles floating around, and there’s no shortage of nutritional options.
As for moisture, there are several ways this component can be introduced. High humidity, flooding, spills, and leaks are a couple of examples. Because wood is porous, it will absorb this moisture, creating an opportunity for microbial growth.
Before you know it, mold on wood can be wreaking havoc on your indoor environment.
Can Mold on Wood Impact Your Health?
Yes, it can. As long as the mold colony is thriving and surviving, it’s releasing spores and fragments into the surrounding area. Some species of mold also produce microscopic toxins called mycotoxins when threatened.⁴
As an added layer of complexity, where mold is found, bacteria are often present as well. This microbial growth further adds to the particle party.
In nature, all of these particles have a big, wide world to disperse through. Growth in a home is not the same scenario. Instead, most of those particles will be distributed throughout the indoor space. And, thanks to modern building practices pushing for net-zero energy efficiency, there’s very little airflow between indoor and outdoor environments. This means that a majority of all of those particles will remain inside until they’re forcefully removed.
As long as the colony exists inside, all of these invisible particles will continue to build up in the home.
The health impact comes due to the size of the particles in question. Classified as particulate matter, these particles are small enough to be inhaled, ingested, and absorbed into the body.⁵ The more time someone spends in the home, the more particles will make their way into the body. Some of the particles are so small that they can bypass the lungs and head straight into the bloodstream.
The immune system will attempt to get rid of all these foreign particles, but it can eventually get bogged down and/or malfunction, triggering a long list of potential symptoms.⁶’⁷’⁸’⁹’¹⁰
Common symptoms of mold exposure include:
- Headaches and migraines
- Rashes and other skin issues
- Chronic fatigue
- Brain fog
- Mood swings
- Anxiety and/or depression
- Allergy and cold-like symptoms
- Digestive problems
- Hair loss
The tricky thing is that no two people will respond to mold on wood (or exposure in general) the same way. One person may have the occasional headache while another person develops over 30 symptoms.
Much more research is needed to better understand how exposure impacts our bodies, but it’s a tough subject to nail down. Genetics, length of exposure, volume of exposure, species of mold, presence of mycotoxins, presence of bacteria, and immune system status all play a role. Those with compromised and developing immune systems, for example, are prone to experiencing adverse reactions faster and to a greater degree.
The potential for chronic symptoms is reason enough to actively work to avoid mold on wood and understand how to treat it properly. That way, a toxic indoor environment will not develop.
What Does Mold on Wood Look Like?
Detecting mold on wood is the first step to success. While the visual component is a key indicator, there are other factors to consider as well.
Visible growth or water damage can both indicate a contamination situation.
With so many species existing in the world, mold colonies can come in a variety of colors, shapes, and textures. Some of the most common colors include green, white, grey, blue, red, black, brown, or a combination of them. As for textures, they could be fuzzy, powdery, velvety, or slimy.
If any type of unidentifiable growth pops up, it's safe to assume there’s a mold problem that needs to be addressed.
As for water damage, discoloration, watermarks, lifting boards, or rusty nails can all indicate a problem.
If you don’t find any visible mold, that doesn’t mean that there isn’t a problem. The growth could be in a hidden location like underneath flooring or too small to be seen by the naked eye yet.
In this case, rely on your nose. Mold growth often creates a damp, musty, earthy smell due to the release of gases called microbial volatile organic compounds (MVOC).¹¹ If you smell this, there’s a good chance that you’re dealing with mold on wood.
Not all mold growth will be visible, and not all mold growth will create a smell. In cases like this, pay attention to your body and how you feel. Have you developed chronic symptoms over time that no doctor can pinpoint a root cause for? Do they flare up inside the home?
Our bodies are amazing warning systems that will let us know when something is wrong. If you start feeling unwell, those invisible particles could be making their way inside of your body and wreaking havoc, causing your body to sound the alarm and say, “Hey, something is definitely not right here.”
How to Remove Mold on Wood
Once you’ve identified that there’s a problem, handling the situation properly is key. Unfortunately, remediating mold on wood correctly can be tricky. Because of its porosity, the roots of the growing colony can penetrate the surface if not sealed, and it is difficult to completely remove. Small particles like mycotoxins can also embed themselves into the pores of the surface, and these are particularly difficult to get rid of.
Hiring a professional for this situation is typically the best option. That way, you can ensure that the issue is resolved and that your home is once again a safe indoor space.
The professional coming in should understand the importance of proper remediation and places your health as the ultimate priority. Their protocol should also be based on three pillars.
These three pillars are:
- Remove the sources
- Resolve the problems that led to mold growth in the first place
- Eliminate all contamination from the space, including other particles such as mycotoxins
If any of these boxes aren't ticked, the project will be unsuccessful. The microbial growth could come right back or contamination could be left behind, allowing exposure to continue. Both of which are home health no-nos.
That being said, if the mold on wood is a small enough issue that you feel confident in handling, these are the steps that you should follow based on whether or not the surface is sealed or not. Keep in mind that the issue that led to the opportunity should also be resolved, or else the microbial growth can come right back.
Steps for Unsealed Wood:
- Use a HEPA vacuum and thoroughly go over the surface:
- Apply 8% hydrogen peroxide and allow this to dry
- Use an abrasive method such as sanding or wire brushing to go over the surface
- HEPA vacuum the surface thoroughly once again
- Spray a botanical cleaner such as Benefect Decon 30 and allow it to sit for 10 seconds
- Wipe with a microfiber towel and then allow this to dry (microfiber towels are 100 times better at wiping away small particles than regular rags)
- Complete the spray, wipe down, and drying process once more using a new side of the microfiber towel
- Dry encapsulate/seal the surface
- When dry, wipe again with a microfiber towel
Keep in mind that when you’re sanding and remediating the surface, particles will become airborne during the removal process Setting up proper engineering controls, wearing personal protective equipment, and creating a containment area should be included to help protect you and your home from the particle party.
Make sure to also deep clean the home afterward to eliminate these particles and to avoid them from spreading to other areas of the home.
Sealed surfaces typically do not require sanding because the roots will be unable to grow within the fibers of the wood. That being said, if the mold grows right back, the process above should be followed.
Steps for Sealed Wood:
Spray a botanical cleaner such as Benefect Decon 30 on the surface
- Allow this to sit for 10 minutes, and then wipe with a microfiber towel.
- Repeat the process two more times, flipping the towel to a new side each time
- Allow the surface to dry completely
- Deep clean the surrounding area
If the situation occurs again, it’s time to call in a professional for help. They’ll be able to determine what the underlying issue is that's allowing for the problem. If the mold is on furniture or decor, your best bet is to toss the item and get a new one.
How to Prevent Mold on Wood
The best way to deal with mold on wood is to prevent it from occurring in the first place. Not only will it promote home health, but it will also save money from costly remediation.
Steps to prevent mold on wood include:
- Seal all wood surfaces: This prevents moisture intrusion from being able to saturate deep within the fibers of the wood itself.
- Decrease indoor humidity: Some species of mold can grow in high humidity. Maintaining indoor humidity levels between 35 and 50% eliminates this opportunity for growth.¹²
- Properly wipe and dry pooled moisture within 24 hours: Keeping wood surfaces dry is key to preventing microbial growth.
- Keep windows and doors closed while the AC is on: When the hot outdoor air meets the chilly indoor air, it can create condensation in areas such as windowsills and door frames, both of which are typically built with wood. If you want to ventilate your home, turn the air off before opening any windows or doors so that this moisture opportunity does not pop up.
- Deep clean often: This removes unwanted particles from hanging out in your indoor space and on wood surfaces. Use a HEPA vacuum cleaner, botanical products, and a microfiber towel to kick those particles to the curb.
- Regularly checking for structural issues: The more you can prevent water intrusion into a home, the more protected any wood material inside will be.
- Use moisture-resistant wood varieties in a home: like hickory, redwood, some species of oak, teak, and white ash.
- Create airflow: This is particularly important in areas like the kitchen and bathrooms. To create airflow, open a window or door when the room is in use and turn on the exhaust fan. Doing this will help pull that moisture-rich air out of the space and replace it with dry air from the outside. Keep the fan going for at least 30 minutes after using the space. If the humidity level will not decrease, consider investing in a dehumidifier.
Your Healthy Home
Preventing mold on wood and understanding how to appropriately handle any situation that pops up is a crucial aspect of home health. Considering how much of our homes are made up of wood, it just makes sense to add this to our knowledge base and our home maintenance plan.
The more we can avoid that fungus among us and the contamination it creates, the safer our indoor spaces will be and the more they’ll promote our ongoing health. When we breathe 20,000 breaths per day and spend around 90% of our time indoors, ensuring these spaces are not toxic should be a top priority.
Health begins at home.™
- Environmental Protection Agency. (n.d.). Mold. EPA. Retrieved from https://www.epa.gov/mold.
- Centers for Disease Control and Prevention. Basic facts about mold and dampness. Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/mold/faqs.htm.
- Lstiburek, J., Brennan, T., & Yost, N. (2002, January 15). Rr-0208: What you need to know about mold. Building Science Corporation. Retrieved from, https://www.buildingscience.com/documents/reports/rr-0208-what-you-need-to-know-about-mold/view.
- World Health Organization. (n.d.). Mycotoxins. World Health Organization. Retrieved from https://www.who.int/news-room/fact-sheets/detail/mycotoxins.
- Taylor, S. (2019, March 2). What three conditions are ideal for bacteria to grow? Sciencing. Retrieved from https://sciencing.com/three-conditions-ideal-bacteria-grow-9122.html
- EPA. (n.d.). Health and Environmental Effects of Particulate Matter (PM). EPA. Retrieved from https://www.epa.gov/pm-pollution/health-and-environmental-effects-particulate-matter-pm.
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- Environmental and Occupational Health Assessment Program, & Environmental and Occupational Health Assessment Program, & Health Science Section, Mold Basics for Primary Care Clinicians (2009). Hartford, CT; Connecticut Department of Public Health. , H. S. S., Mold Basics for Primary Care Clinicians 1–10 (2009). Hartford, CT; Connecticut Department of Public Health.
- Curtis, L., Lieberman, A., Stark, M., Rea, W., & Vetter, M. (2004). Adverse health effects of indoor molds. Journal of Nutritional & Environmental Medicine, 14(3), 261-274.
- Bush, R. K., Portnoy, J. M., Saxon, A., Terr, A. I., & Wood, R. A. (2006). The medical effects of mold exposure. Journal of Allergy and Clinical Immunology, 117(2), 326-333
- Fisk, W. J., Lei-Gomez, Q., & Mendell, M. J. (2007). Meta-analyses of the associations of respiratory health effects with dampness and mold in homes. Indoor air, 17(4), 284-296.
- Wild, C. P., & Gong, Y. Y. (2010). Mycotoxins and human disease: a largely ignored global health issue. Carcinogenesis, 31(1), 71-82.
- Bennett JW, Klich M. Mycotoxins. Clin Microbiol Rev. 2003 Jul;16(3):497-516. doi: 10.1128/CMR.16.3.497-516.2003. PMID: 12857779; PMCID: PMC164220.
- EPA. (n.d.). A Brief Guide to Mold, Moisture, and Your Home. EPA. Retrieved from https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home#tab-6.
- Environmental Protection Agency. (n.d.). What does mold smell like? EPA. Retrieved from https://www.epa.gov/mold/what-does-mold-smell.