I'm in the process of renovating my garage. There was a 1 in. gap due to rotting wood where the roof shingles meet the fascia (part where gutter is attached). The discolored wood is near the gap.

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A few joists are the same color as well. I sprayed with Vinegar and soap - nothing really changed. I avoided using bleach due to the wood being porous. Any idea of which type of mold this is? Does the wood need to be replaced or can I use some type of cleaner (concrobium, borax ect). I was also thinking of scrubbing the wood w/ vinegar & baking soda again, wiping with microfiber cloth, spraying concrobium and then painting over with an anti microbial primer sealer.



1 Answer 1


On my phone it looks like the beginning of dry rot. I would use a flat blade screw driver and press where you think it is the worst if the blade doesn't sink in the wood is ok. Double check with the same pressure in an area that looks clean.

I think you will find the wood is ok but now you want to stop it from getting worse. I use a 3% hydrogen peroxide solution and water: this will kill the fungus without the smell of bleach, but is tougher to find than bleach. A dilute solution of chlorine bleach and water will also work; being in the attic the smell may not be a problem in the living space if the roof is well ventilated.

If you do use hydrogen peroxide remember to add it to the water rather than the other way around (AAA=Always Add Acid).

  • hydrogen peroxide solution is sold at grocery stores an "chlorine-free bleach" or "oxygen bleach" .... you can also buy it at livestock supply stores (it is much stronger there and you will have to dilute)
    – jsotola
    Jun 18, 2018 at 2:48
  • I think the grocery stores stuff or for human use is only .3% I usually get mine from a local chemical supply this is close to 30% I will check the livestock supply I have never thought to ask but because of our horses am there almost weekly.
    – Ed Beal
    Jun 18, 2018 at 14:59

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