Remove Mold From Wood

Remove Mold from Wood Guide

Wood is a hygroscopic material, which is a fancy term that means it likes to soak up and retain water (think of a sponge).  This makes sense, since wood comes from trees, which soak up water to grow.  While this is good for the tree, its not good for your lumber, furniture, or trim. Let’s go through the steps and talk about some specific issues when removing mold from wood.  Keep in mind these steps assume the mold covers a relatively small area (i.e. less than 10 square feet).

remove-mold-from-wood

What you got there? Mold on wood? We can help with our Remove Mold from Wood Guide.

Step 1- Choose a cleaning solution

There are many commercial products that are pre-mixed to tackle mold problems.  To remove mold from wood, make sure the cleaning solution  fits the situation.  For example, if you are trying to remove mold from wood that is finished or painted, you can rely on more mild cleaning solutions because you don’t have to kill the mold, you can just remove it.  If the mold is established below the surface of the wood, which often happens on unfinished wood, you will need a solution that will penetrate the surface and kill or inhibit the mold.  Here is a list of suggested solutions to choose from depending on the situation:

Remove mold from wood – finished or painted wood:

  • Mixture of household detergent and water
  • Commercial mold removal product (always follow manufacturer’s instructions on the label)
  • Distilled Vinegar
  • Baking Soda -Detergent Solution (1/2 cup baking soda, 1 cup water, 1 Tbsp mild liquid detergent)
  • Borax Solution (1 gallon of water to 1 cup of borax, or 1 part borax to 16 parts water)

Remove mold from wood – unfinished wood:

  • Rubbing Alcohol or Denatured Alcohol
  • Commercial mold removal product (always follow manufacturer’s instructions on the label)
  • Distilled Vinegar
  • Borax Solution (1 gallon of water to 1 cup of borax, or 1 part borax to 16 parts water)
  • Baking Soda -Detergent Solution (1/2 cup baking soda, 1 cup water, 1 Tbsp mild liquid detergent)
  • Bleach-Detergent Solution (Recommended by the US Forest Products Labratory – 1 part household detergent, 10 parts bleach, and 20 parts water)

Warning:

Never mix bleach with a product that contains ammonia.  It will produce toxic fumes that can cause serious illness or death.

Bleach

Bleach only kills mold spores that are on the surface of the wood.

Special note on Bleach:

When working with wood, you should be aware that bleach can only kill mold spores that are on the surface of the wood.  Mold in wood, however, tends to grow and establish roots below the surface and into the wood fibers.  Due to the chemical makeup of bleach, it does not absorb into the wood, and it is possible that you will see the mold re-establish itself after you have cleaned it with bleach.

To address this problem, several companies have produced mold removal products that include surfactants.  What the heck is a surfactant you ask?  To put it simply, a surfactant is an additive that allows the detergent or bleach to absorb deep into the wood fibers.  It does this by reducing the water surface tension, but that is something for another discussion. The detergent in the suggested mixture above helps to allow the bleach to get down to the roots of the mold.

So, the bottom line is you can elect to use bleach, but keep in mind that there are better products to remove mold from wood.  If using a commercial product, look for an EPA registered mold removal product (regular household bleach does not have such claim).

 

Step 2 – Put on Protective Clothing and Make Safety Precautions

mold-removal-safety-gear

Mask, gloves, glasses and coveralls.

Depending on the severity of the cleaning solution that you chose, you will need to take some safety measures in order to keep yourself free from harm.  Before you try to remove mold from wood, we recommend the following:

  • A respirator, or air mask, that is adequate for blocking mold spores from entering your lungs.  The EPA recommends a N95 mask or equivalent.
  • Rubber or Nitrile gloves.
  • Safety goggles that do not have air vents in the sides.
  • If you are moderately sensitive to mold exposure, we recommend wearing coveralls to protect your skin as much as possible.  If you are severely sensitive to mold exposure, we recommend getting somebody else to perform the task.

If you are using a product that has strong or dangerous fumes, also make sure your are working in a well ventilated room.

 

Step 3 – Apply the Cleaning Solution and Scrub

Apply the cleaning solution that you have elected to use.  Start by testing the solution in a small, hidden area of the wood to make sure the solution does not cause any discoloring.  You can do this with a spray bottle, a lightly damp rag, low-abrasive brush, or a srub pad.  If you are working on finished or painted wood, we do not recommend using a brush unless you plan on re-finishing the surface.

The key is to apply the solution lightly, but enough to cover the mold.  Too much solution can actually add to the dampness of the wood, which is part of the problem in the first place.

Let the solution sit for a few minutes, then scrub the area in circular motion with your rag, brush, or a scrub pad.  Using a disposable towel, or a towel you can disinfect with bleach later, wipe of the area and the excess.

Continue this process until the mold is removed from the wood surface.

Step 4 – If Needed, Lightly Sand the area

If you are working with finished wood, then this step will require you to re-finish the area that you are sanding.

If the mold appears to be established deeper into the wood, you will likely need to lightly sand the area.  This helps to remove the mold roots on the surface, and gets you deeper into the wood fibers.  You should sand the area while it is still damp to discourage mold spores from spreading through the air.

After sanding, repeat step 3.

 

Step 5 – Clean Up and Let Dry

After you remove mold from wood, clean up the area and either dispose anything that has had contact with the mold, or clean it with a proper detergent or fungicide.

Let the wood dry by keeping in a warm, dry, sunny area with good ventilation.  If you live in an area with higher humidity, you may want to place it in a room with a dehumidifier.  Leave it until the wood looks and feels dry.

 

Step 6 – Check for Signs of Mold

After the wood has dried,  look to see if there is still mold and if the area smells moldy.  Sometimes the wood will be stained from the mold even though the mold is gone.

If the mold is still visible or the odor is still strong, repeat this process again.

 

Step 7 – If Needed, Re-apply Protective Wood Coating

If you have scrubbed or sanded finished wood, you will probably need to re-apply the polyurethane, lacquer, protective stain, or whatever finishing product that was on it.

 

You have just read our Remove Mold from Wood guide!
We hope this was helpful!

-David
Author

 

39 thoughts on “Remove Mold From Wood

  1. we have white mold on paneling in a cabin. From leaky roof over winter that we are in the process of fixing. What is the best solution for paneling? Does it have to be removed? Cabin is isolated with no running water or electricity.

  2. Hi Jane,

    A lot depends on what the paneling is made of. A lot of paneling is made from processed wood, like mdf. If that is the case, it will likely need to be removed especially if the mold has saturated down into the fibers. Processed wood products are similar to drywall in that it is almost impossible to get the mold out if it has formed deep inside the material. If the mold is only on the surface, there is chance you could salvage it by cleaning off the mold. Check out our page on how to kill mold to see which method might be best for you. Good luck!

  3. I have white mold on many items in my basement (finished wood, unfinished wood, plastic, rubber, vinyl, books, metal). Except for a couple of pieces of furniture, you can’t see any mold unless it is dark and you use a flash light. I will be throwing most everything in the trash. However, for those items I want to keep, I would like to clean. I tried the borax, distilled vinegar, water mix on finished wood and that did not work. I would like to try the mix with detergent. I see this mentioned many times in relation to cleaning mold, but no one specifies what kind of detergent. Is it dishwashing detergent such as DAWN or is it laundry detergent such as TIDE? Or is it something else? Please give me a specific example of what detergent, brand name. Thank you, cindy

  4. Hi Cindy, detergents typically refer to either laundry or dish detergents. The importance of detergents is that they are surfactants that reduce the surface tension of water, allowing the water to penetrate and better “wash” the area. Either of the detergents you mentioned should be fine. Good luck. If the white mold doesn’t disappear, it may have grown beyond the finish, and actually moved underneath into the wood fibers. You would then want to look at the instructions for removing mold from unfinished wood because the mold is now into the actual wood instead of the just on the finish. If the mold has grown too deep, you may need to sand your furniture down, clean it, and then re-finish it.

  5. We have white mold on the bottom side of a deck around a pool inside a screen enclosure with an outdoor shower and hot tub. Obviously it stays damp to say the least. It is rotting the wood and I was replacing wood when I found it. Is it safe to say that the wood would be easier replaced than cleaned? The deck is also close to the ground (less than 2ft). I’m thinking time wise it would be more beneficial to replace rather than clean. What are your thoughts?

  6. I have cleaned up all the except under the wall studs where it meets the floor. Is there any recommended method baring removal of the bottom stud plate? I have sprayed the bleach solution around the base and have dried the area with a floor heater. After 5 days there is still some moisture. Not sure what else to do and I would like to put my home back together. When I do, should I paint the interface with Kiltz or leave open? Thanks for any ideas.

  7. I have white mold on a 400 year old grapevine coffee table. It was in the living room when there was a flood in the kitchen (broken pipe to the ice cube maker) and the water spread over the floor into the living room, etc. Now there is a white mold over most of it. What can I do about it. It is a beautiful table and is worth over $2000.

  8. I recently pulled up the rug in a room we plan to put hardwood flooring down and found a black stain in the subfloor and along the edge of the drywall. We used to have a fish tank there but that was over 5 years ago.

    Could the black stain in the particle boards be mold, and if it is, could it still be active after 5 years of no water source?

    Thank you for any advice you can give.

  9. Hi Rich. It is possible that the stain is mold since there is a likely suspect (fish tank) that could have either slowly leaked or had condensation that dripped periodically on the floor. We tend to be more cautious, so we would say when in doubt, throw it out. Typically, dry mold isn’t active. But that just means it is not currently growing and destroying your subfloor or drywall even more. On the other hand, even higher levels of humidity in the air can reactivate the mold. It then sprouts tiny hair-like spores that start to produce new active spores. The good thing about this possible mold problem is that subfloor and drywall are both relatively easy to replace, even if you just cut out small sections.

  10. Hi Judy. Depending on whether the table has a finish, like polyurethane or lacquer, you can refer to the methods above in the article. In this case, it would be better if the table did have a finish because it might mean the mold has not penetrated into the wood fibers. If the wood is unfinished, you can try the methods above. Since this table is quite valuable, both in dollars and historically, you may want to contact a mold specialist in your area to get an opinion. It might be worth a minor consolation fee to have someone come out and look at.

  11. Hi Joe. One thing you could try is using an air compressor to blow strong air along the bottom. This can force the moisture out of the crevasses where it has ambient air to dry. If you live in an arid or semi-arid climate, you might be able to put Kilz on it once you get it as dry as possible. The bleach soak was a good move because some of that bleach is also in those moist areas too, which is inhibiting future mold growth. We’re thinking you could get away with the Kilz as long as this area of your house does not get much moisture. A baking soda or borax solution can be used to inhibit future growth , so you could look into that too. The only 100% solution to this problem, however, is to remove the floor plates and clean it up.

  12. Hi Donnie. It sounds like this is a problem that will continue to come back. Damp, dark places with weak air circulation is like mold heaven. Since this is outdoors, it typically doesn’t pose as high of risk because of the air circulation, but can still put damper on things, especially if you can smell it. To answer your question, you will have to determine whether its better to replace it. It is probably safe to say, however, that the mold is deep inside the wood fibers. If the wood is fairly old, odds are it will be easier to replace that clean up.

  13. Hi David,
    I had items in a storage unit for a year during our area’s wettest summer. I found mold/mildew on some items, mostly picture frames and books. I got rid of those items but kept everything else that didn’t appear contaminated. Could mold be present on my other items and I just can’t see it? It’s odd that some things were obviously damaged and other things look and smell fine.

  14. We have spring air on our furnace which provides humidity. The house is ten years old and very tight. A lot of moisture appears on our windows which are wood. Now we have black mold appearing on every window. To top it off, I have lupus with no immune system and should not be exposed to mold. What is the best way of taking care of this problem?

  15. Hi David,
    I have a knee wall in my Cape house and in that knee wall is a duct for the heating over the entire length of the house. I recently saw that all the insulation in the knee wall is wet and the wood behind it had ice crystals on it at this time. I am planning to have the insulation removed and having spray foam blown in between the studs when everything has dried. If there is mold on the wood between the studs, should that be removed or can they just put the spray foam over it and cover it airtight?

  16. I had a food storage room in which a food item leaked and then mold grew from it. Do I need to be as careful in the clean up? And do I use the same method described above?

  17. We have an outside porch Yat has a cypress T & G ceiling. We live in South Carolina new the ocean and humidity is a serious problem. This spring we noticed some dark old on some of the boards. Our concern is that by using a chemical to rid the mold our wood will become discolored orbleached. Is the a process that will insure a positive outcome without the danger of discoloration?

    Thanks TS

  18. Great tips but I didn’t see my specific problem. I have a 1200sqft out building with a concrete floor and finished walls but no ceiling but has an insulated roof. It sat closed up for a year or so and has incredibly high humidity inside. I’ve had mold grow on several items and my fear is the exposed rafters are covered in mold although I don’t see any masses of mold. I’m somewhat sensitive to mold and dust and if I spend an extended amount of time I can feel it in my sinus and throat. Can I just spray a bleach/detergent solution on without scrubbing it off or is there a better solution for me?

  19. I have white mold on the wood in a sun room we have put bleach on the wood but it has not died I don’t know what to do. I think that the mold that me and my family are trying to remove is water damage of sun damage because I put full bleach with no water on it and it comes back when it dry’s out. the wood is unfinished Tung and groove wood

  20. I assume the black on the sills of my porch windows is mold or mildew. The wood is painted. What is the best solution to remove it?

  21. I have white mold on the ceiling of a basement bedroom closet that is about 7 ft x 2 ft. The ceiling is made of drywall. What do you suggest???? It is only in that one area.

  22. I recently bought an old wood bread box and it smells like mold the bread we had in it smells like mold how do you remove the mold smell from the wood bread box?

  23. Our camper was closed all winter. After I opened it and left it open “to air it out” for a couple of weeks I noticed a fluffy green something growing on the wooden cutting board that covers the stove top and also on the fronts of the cabinet doors. What should I have used to clean this? I used Lysol All-purpose Cleaner and then wiped the cutting board with mineral oil.

    What WAS the stuff? And what should I have used to clean it? I wound up sick with a horrible sinus infection that the doctor said probably resulted from that.

  24. I have removed mold from surface of basement unfished rafters and applied borasol mc would it be wise to varnish after it’s dry or leave as is.

  25. Keri,
    I have done the same thing with storage units. It is possible that some things get mold, while others don’t. It is primarily a function of whether mold spores land on that item AND it has the chance to take route. If you don’t see any mold, the second test is whether you smell it. If the object smells musty or moldy, it might have mold growing in it. As indicated in on this page, if it is a material that can absorb moisture on the surface, it is more likely to have mold in it, and it will be more difficult to remove. If the surface is nonporous (doesn’t absorb water), then you could probably get rid of the mold using one of the methods on this page.

  26. Danelle,
    Because of your immune system situation, you should not mess around with this. My advice is to contact a mold removal specialist. Click on this page for some good advice on selecting a mold removal contractor.

  27. Hi Bert,
    Depending on the extent of the mold between the studs, you may or may not be able to get away with covering it up. If the mold is minor, or not visible, you can treat the wood with one of the methods on our “get rid of mold” page, here is the link. There are some commercial products that you can spray to clean and retard any future growth of the mold. The key is making sure the wood gets dry first, and stays dry. If you live in a high-humidity area, make sure you give it a good cleaning and drying before going further. You may even consider just replacing it if you can. If the mold is highly visible and covers a large area, its best to get a professional, or remove the wood. Good Luck!

  28. Hi Teena,
    For the most part, mold is mold, whether it is from food or rotting wood. Unless you have a high sensitivity to mold, you should be able to just clean up the area and through the bad food away. If the mold grew on the wood shelving or the wall, then yes you will probably need to use the same method.

  29. Hi Tom,
    I honestly have not worked with cypress wood much. The good thing is that cypress is rot-resistant, unlike softer woods such as fir or pine. For this reason, you should be ok with a more mild solution to cleaning the mold. You could try the rubbing alcohol or the borax solution first. I actually like the borax solution because its relatively safe to use, and since it has such a high ph value, it actually helps prevent the mold from returning. You can explore more mold cleaning solutions here.

  30. Hi Chris,

    If there is a way to inspect the rafters, I would do that first. A visual or sniff (smell) inspection should be made to see if you detect the presence of mold. Make sure you take proper safety precautions since you are somewhat sensitive to mold (or have somebody else do it). Whether you need to scrub or not really depends on the extent of the mold problem. If the mold is not visible, but you are just taking a precaution, then a spray would probably be enough, as long as you take measures to reduce the humidity or keep air movement in the building. If the mold is visible, or looks heavily entrenched into the wood fibers, then you probably will need to go to the next level and do some scrubbing. Again, use good safety precautions. Also, you might want to check out our page on preventing mold to help keep it from returning. It sounds like getting some air movement and dehumidification/air conditioning in there would be a big plus for you, if possible.

  31. Hi Karl,
    It is possible that the white stuff you see is actually wood that has been stained by moisture, and maybe mold. I would first think to smell the area to see if you detect a musty, moldy odor. Next, did you try scrubbing or wet sanding the area? By doing this, you will be able to see if it is only on the surface or if it is embedded deep into the wood. After scrubbing/wetsanding, apply the bleach solution indicated above on this page. Remember that adding a detergent (not ammonia) to the solution will help the bleach to penetrate into the wood. If you do this, and the white area is still there but there is no odor, it is likely that the wood is just stained from the mold and water. Most importantly, ensure the environment of your sun room is not conducive to mold growth. Proper air movement, lower humidity levels, and lack of moisture source (leaks, etc) are key. Good luck!

  32. I have discovered a small patch of white mold on the under side of roof decking by a chimney. The patch runs on the plywood along the rafter framing about 4-6 inches in each direction. The exposed mold can be treated but there must also be some issues sandwiched between the rafter and plywood decking. Is there some way of treating this as well?

  33. I just moved a window box from the end of our table (near the window) of our 5th Wheel. W live in a very dry Arizona climate and the window box was not suppose to have any holes. The plants died in it so I guess I didn’t water it very much but must have missed some time or another and watered the top of a birch table. As I removed the linen that was under the box there is black mold. The table, since it it near the window was dry I thought, so I wiped up what I could and then applied lemon oil in the form of Old English Lemon Oil. Now I need to get out the rest of the black. I am going to wash off the lemon oil with detergent and Bon Ami. What else can I do? Thanks for any help you send.

  34. I have a greenhouse which is built on a decking platform. To improve winter warmth, I have put some dense sponge tiles on the floor. Having lifted them for cleaning I have found that there is a coating of white mould or fungus, quite thick, underneath on the decking. Dose this need scraping off first or treating with the solutions described above?

  35. I just went thru hell in my house over mold – We have 3 kinds of it and it is still going on.
    What I have learned that kills the “white slimy” mold is Hydrogen peroxide –
    Like a cut on your finger, when the hydrogen peroxide dries, it burns like hell on your skin.
    It does the exact same thing on wood. It burns it off and out of bare wood. I sprayed it good; as in soaking it; let it dry for a day, went back that next evening and soaked it again leaving it to dry the next day again. 3% over the counter worked well.
    But here is the thing and I am learning this too as of late – its not just about “killing” it –
    you have to remove it – even tho spores are dead, they can still release allergens and spread. So once you kill the spores, get a good HEPA VAC and suck them up.
    Our house is not done yet, so I am sure there is more that I will be learning –
    Hope this helps anyone who needs it.

  36. My child has a tree house that she built with her Dad 10 or so years ago. It started showing signs of mold and looks almost unsafe because the wood looks so weak, but when she plays on it, it proves rather strong. I was wondering if it was ok to just paint over it. I am not sure if any of these solutions will last, considering that its outside all year round, but I don’t want the wood to get so weak from the mold that it is unsafe for her to play. Any advice?

  37. We are remodeling a home and have pulled out two vanities that smell musty. I have cleaned with Clorox 2 and wood cleaner inside and out. I have let them dry out and they still have a musty odor. They did not have any visible signs of mold on the wood. Any suggestions before we have to purchase new vanities?

  38. We got a beautiful wood bunk bed from my sister 3 weeks ago and part of the items were white from strong with mildew smell…. We have tried what seems like everything (vinegar and water) (10/20 bleach with water) drying it out in the sun as much as we could constant running of dehumidifier which leaked half the time with the bucket tipping over and soaking our fake wood floor….Along with air purifier, and running the air conditioner with occasionally of just opening the whole room up to air out<— that actually worked the longest which was 1.5 days
    Nothing has worked permanently! My 3 year old wake up with a hacky cough every morning and though the white color is gone the SMELL has not
    I'm ready to do a commercial sold mold remover other site said Wet and Dry Indoor would be best but you seem like you REALLY know what your talking about so any recommendations I am yours to command 😉
    On a second piece I noticed in the basement that same gray/white powder color on the main beam below their room could that be what I smelling because you don't smell anything in the basement or any recommendations to take care of that too

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