I purchased this house about 5 years ago and the crawl space was checked out by a home inspector and he said it looked fine but it would not be a bad idea to install some sort of vapor barrier. The floor of the crawl space is approx. 25ft x 19ft is 75% covered in plywood squares that are approx. 2.5ft x 2.5ft in size arranged in a grid to make a makeshift surface for storage. Below the plywood was gravel and below that is dirt.

I ended up doing the vapor barrier with 7mil plastic and called it a day. However, and I want to acknowledge that this was a terrible idea in hindsight, I placed the barrier on top of the plywood. As a result, there are many spots with yellow mold growing on them and the wood in the corners is very wet at this point (we just had heavy rains).

I went down there with a respirator, removed all of the boxes we were storing down there and took some pictures.

I called a local mold remediation company to come check it out and he said that the mold didn't look too bad and that in all honesty the vapor barrier did its job in preventing the mold from spreading up to the actual joists and support wood that's on the ceiling of the crawl space. He did say there were a couple of spots of something on a few of the joists but did not clarify if they were mold or not. During his inspection he also recorded the humidity in the crawl space of 47%.

He gave me a quote for $8000 which seems a little high. I am going to get a few more quotes but in all honesty I already have the PPE I need and if the other quotes are just as high I am planning to demo it myself by starting at one end of the plastic and slowly rolling it up and as I reveal each plywood square, place it into a large trash bag and take it to the dump.

Afterwards I will purchase a dehumidifier specifically designed for crawl spaces and place that in the center of the crawl space.

Because most of, if not all, of the mold is contained to the plywood squares, what else do I need to purchase/be aware of before I tackle this myself?

  • Sounds like you have it together (tyvek suit, p100 mask, gloves, right?), but the thought of bagging and hauling 15 sheets of icky plywood makes me want to search for “junk hauling service”. In my expensive area, I’d be under 500 bucks and I’d consider it money well spent. Sep 1, 2023 at 1:00

2 Answers 2


Yes, you might be able to tackle this on your own, however, are you going about it the right way is the bigger question.

Mold can be extremely dangerous. When mold is disturbed, it releases spores into the air which can potentially cause it to spread even more exacerbating the issue.

The quote you got, while it may seem high to you, that technician probably has extensive knowledge on how to properly remediate without making the problem worse.

Yes, anyone could throw on a tyvek suit and a P100 respirator and bag it all up, drag it out and call it a day, but, are you willing to take the risk?

If you are dead set on doing it yourself just make sure you are aware of the risks.

  • How could this mold spread more? It's already saturating the environment. Quick-n-dirty is just fine, then dry things out.
    – isherwood
    Sep 1, 2023 at 14:23
  • Not all molds are out to kill you. Yes, some are bad for you, but this is mostly FUD.
    – FreeMan
    Sep 1, 2023 at 14:25
  • 1
    @isherwood Mold 101, disturbing mold releases spores. Which can cause it to spread....*more*. If the spores land on stuff and isn't neutralized I can grow, right?
    – matt.
    Sep 1, 2023 at 14:48
  • Haul out the moldy plywood.
    • Consider getting rid of the plastic, too, though it's most likely OK.
  • Spray bleach on anything that looks like it might be mold on any of the structural wood.
  • Let everything dry out for a bit (47% humidity? Man, that'd be a nice, low number around here!).
  • Replace vapor barrier
  • Replace plywood if desired.

One missed step:

For the ultra paranoid, suit up, collect a mold sample and send it off to a lab for testing. That way, you'll know if you've got something potentially dangerous (to breathe) or if it's a mold you can safely eat. There are 1000s, maybe hundreds of 1000s of molds out there and they're not all out to get you.

Otherwise, sounds like a pretty reasonable plan to me, and shouldn't cost $8000 to DIY it. You might have to pay a bit if you haul it all to the local dump, but my guess is < $100 in most locales (haven't hauled stuff to the dump in ages, so that may be well off today). You could probably get away with cutting up the plywood to fit in your garbage can and chucking several pieces a week in there until it's all gone.

  • 1
    Use diluted bleach. Full strength can be harmful. Sep 1, 2023 at 15:49
  • @SteveWellens Especially in an enclosed area with minimal air flow and a non chemical rated respirator.
    – matt.
    Sep 1, 2023 at 17:47
  • Weird, random drive-by down vote. Haz a sad. Gets over it...
    – FreeMan
    Oct 1, 2023 at 11:51

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