Anti-mold treatment for wood and insulation under the house?

[Candace]

Hello all DIYers!

I'm wondering about DIYing an anti-mold treatment for wood and insulation under my house.

I live in southeastern Virginia, where humidity is fairly high a lot of the time. I just had my annual termite inspection. Hooray, no termites! However, the nice young man showed me the 18.5% reading on his moisture meter used to measure moisture on the wood beams under the house. I live on a hill, and the crawl space is easily accessible via a door. In half of it, it's easy to stand up. In the tightest part, everything is still easy to reach on one's hands and knees. The crawl space has good ventilation now.

In years past, the moisture reading was more like 8%. Today it was 18.5%. The guy said that at 20%, they would recommend an anti-fungal treatment to be sprayed on the wood and insulation that's under the house. We have the pink insulation, and parts of it are hanging down a bit. It was also easy to see that there was visible mold (itty bitty spots) on the wood and insulation close to the door. I never saw that before this year, and I've had the house for six years. He said they come in and spray some kind of treatment on the wood and insulation. I'm thinking that sounds pretty easy to do myself.

Also, he said that many people are starting to take out their pink insulation that's supposed to keep the floors warm during the winter, because of the mold problems. He said that they would then install a de-humidifier under the house that would keep the moisture out. He also seemed to be suggesting that it would help with any cold temperature issues under the floor, which seems dubious. Also, doing this obviously mean buying a dehumidifier, running power down there for it, and also installing a drain to get the water away from the house from the dehumidifier.

It seems to me that I should be able to DIY a mold treatment, and repeat every year or so if the humidity level is near or above 20%. I don't see why I'd need a dehumidifier if I do this, unless the moisture level in the wood goes above 20% and stays there. Does anyone have any experience with this, and/or any product recommendations, safety tips, gotchas, etc? Also, I don't know how much the wood moisture content is apt to vary with the weather, time of year, etc., but I definitely saw little teeny dots of mold today that I hadn't seen before. So it seems like something to address.

Thanks for any advice.

[affordablehousing]

Boracare with moldcare. Mix it 5:1, ~$120 a gallon at DIY pest care. Wear gloves and goggles and spray it on. One and done, never need to repeat. Make sure you have a good drill and paddle mixer to mix it before you put it in the sprayer. It's essentially a borate salt that penetrates the wood and remains in the wood for the life of the lumber.

[bacchi]

Where's the moisture coming from? Air, ground, a stream in your crawl space?

[Candace]

Boracare with moldcare. Mix it 5:1, ~$120 a gallon at DIY pest care. Wear gloves and goggles and spray it on. One and done, never need to repeat. Make sure you have a good drill and paddle mixer to mix it before you put it in the sprayer. It's essentially a borate salt that penetrates the wood and remains in the wood for the life of the lumber.

Thank you so much!

[Candace]

Where's the moisture coming from? Air, ground, a stream in your crawl space?

It's very humid here in southeastern Virginia. There's no stream in the crawl space (!). The dirt floor is covered with thick plastic. The moisture should be coming from the air.

[ncornilsen]

Another alternative is to make a conditioned crawlspace. You eliminate the foundation vents, put down a thick vapor barrier to seal out soil gases, put some insulation on the stem wall, and dump 50CFM/1000SQFT (IIRC) of conditioned air into the crawlspace. You would eliminate the floor joist insulation.

My house is setup this way, and the hardwood floors are super comfy in the winter.

[Candace]

We're at least going to start by putting down more plastic on the floor (dirt). There are some places where it's ripped and soil is showing through.

[ChpBstrd]

I’ve often wondered if this is an opportunity to use up the 5-gallon buckets of leftover/old exterior paint or polyurethane that sometimes appear at my local Habitat for Humanity store, estate sales, etc. for $5-20 per bucket. You could mix colors, etc. Just slop it on with a broom because visual quality doesn’t matter. Throw in some cheap algae treatment for good measure. This would limit the growth potential of mold and fungi regardless of humidity. However a future house inspector would wonder what the hell happened!

Side note: Check your gutters and ground drains. One overflowing gutter could be your entire issue. Obviously improve your plastic coverage too.