Dealing with Mold or Fungus on Barn Wood

by Jason
(Crested Butte, CO)

A friend of ours just gave us a bunch of barn wood that has been sitting outside his house for a few years.

Some boards have a light white looking fungus.

We want to use it as trim to finish our basement. We live in a very dry climate in the Colorado mountains.

The wood has no signs of insect infestation. Any suggestions on how we need to treat this wood? Thanks for taking the time to help us.

Hi Jason,

It could be mold or another type of fungus. Either way the best thing to do is to dry it to about 6% moisture content.

If it is mold it will look a little fuzzy. In either case you will want to wet it down so the spores don't fly around in the air and then wash the mold off with a vinegar solution. This will discolor the wood, so try it on a small area before you go to far. Then you can sticker the wood. (Separate each layer of the lumber stack with 1x1 pieces of wood that run perpendicular to the stack.) It would be best if this is done in a heated area with fans blowing on the stack. Or it could be done outside in the summer with a canopy over the stack to protect it from rain. Whatever you do, do not cover it with a tarp or plastic. This will lock in the moisture that is already in the wood and cause the mold or fungus to grow faster!

You will want to check the stack after 2 or three weeks to see how dry it is. You will need a moisture meter for that. I bought one on ebay not long ago for about $15. It wasn't the greatest moisture meter by far but it was sufficient to check a few boards.

Keep checking the moisture until it gets to around 6% to 8% moisture content.

Also be sure to check the moisture of the air in the environment your lumber stack is in. Just hold the meter up in the air and hit the button. If the Moisture in the air is higher than 8% then the wood will never get that dry. Wood will always acclimate to the environment it is in.

If you can't live with the discoloration effect,or you can't get the wood below 8% then I would recommend having it dried in a kiln designed to dry lumber. A kiln will raise the temperature enough to kill the mold or fungus.

Best of luck to you in your project, and thank you for using reclaimed lumber in your project.

Comments for Dealing with Mold or Fungus on Barn Wood

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Feb 01, 2017
Be careful
by: Mike

The fact that the advice starts off with , " it could be mold or it could be fungus" is a huge red flag. Mold is fungi. Same thing. This person does not understand the potential hazards of indoor mold. Also wetting down mold to control spores is not responsible. In fact, it may release more spores. Bleach does not kill mold. Period. Vinegar on its own will not do it. Get a professionals advice.

Feb 01, 2017

by: Aaron

Yes, technically mold is a type of fungi, but people don't think if it that way, if it's mold it's mold. You don't look at mold and say "Oh look, there's some fungi" So making a distinction is important for clarification. Furthermore, not all fungi that grows on wood is mold. Again, therefore clarification in layman's terms is necessary.

I never said bleach or vinegar would kill mold. What kills the mold is drying the lumber out. Using bleach or vinegar IS an effective way to remove mold stains and to severely reduce the population of spores.

No, it doesn't kill it completely but it does remove most of the spores. Most molds are not toxic, but you should always use caution when dealing with mold, just in case it is. When in doubt, don't.

Wetting moldy areas IS an effective way of keeping spores from getting airborne and breathable. It's not going to remove the mold by itself of course, and if that is all you do then yes, you will spread it. But that is not the entirety of the process I laid out above. If you don't believe me then maybe you will believe North Carolina State University.

"Method 2: Damp Wipe

Whether dead or alive, mold is allergenic, and some molds may be toxic. Mold can generally be removed from nonporous (hard) surfaces by wiping or scrubbing with water, or water and detergent. It is important to dry these surfaces quickly and thoroughly to discourage further mold growth"

https://www.ncsu.edu/ehs/www99/right/handsMan/air_qual/mold_remediation.htm

Air and kiln drying the lumber is the next step and IS an effective mold remediation process.

The dangers with dealing with mold on a stack of lumber outside are almost non existent. I guess if you stick your face next to the mold and wipe it vigorously with your hand toward your face, then yeah, you might have some health problems from that. But use some commons sense!

The entire process needs to be done outside.

You can, effectively remove mold from any lumber with the methods I described above. If you don't want to take the risk, then don't do it!

But really, the risks are very low. In the end, you need to make that decision on your own.

Apr 23, 2019
Newly build barn NEW
by: Jill Rosinski Gloster

Our new barn has black mildew inside and outside. We haven't painted or stained yet. Should we remove the mildew first or what. My husband says yes I say no. Help us before we paint or stain. Thank you so much. Jill

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