Recently I fixed a leak which was causing moisture related issues (obviously). Upon doing some clean up of the area before reinstalling drywall, i noticed some dark spots, likely mold, on the wood.

I have applied several rounds of treatment to the wood including, soap and water, bleach with water, baking soda and vinegar, and some light sanding. Each time wiping down and thoroughly dried the affected areas.

The wood when dry shows no obvious signs of mold, but when spraying down the wood one last time with a bleach and water solution for peace of mind, darker spots were revealed which were not visible when dry.

Could this be embedded mold and is additional sanding/treatment necessary? Or considering now that the leak/source of moisture is now no longer present am I safe to install new drywall?

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2 Answers 2


All wood products are loaded with mold spores. I work in a lumber mill all the lumber is sprayed with a fungicide to stunt the growth for a month or two. When the wood is dry and not exposed to moisture there will be no growth. There hundreds of different types of mold and only a few are hazardous, so yes there is mold and fungi in your wood. Do you need to do anything? No . You have fixed the moisture problem now close things up and don’t worry about it. Untreated wood at the mill is black in a short time. When I worked n ply wood actual mushrooms would grow in the edges of the veneer stacks. Not trying to scare you but the only way to get rig of the mold and fungus is to replace the wood with metal.

  • That is completely fair, just wanted to do some due diligence before reassembly. I am more familiar with working with metal and know the concerns regarding moisture and rust (own/owned too many old cars), but working with a more organic material such as wood, was not sure if this was sufficient.
    – John
    Feb 19, 2020 at 0:46
  • 1
    Looks like water stains to me at the butt joint. +
    – JACK
    Feb 19, 2020 at 1:48

The wood is stained is all. It'll be hidden after covered with wall covering. I would not worry about it. You're safe to cover

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