Crawl space moisture problems


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Old 05-31-24, 08:39 AM
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Crawl space moisture problems

Iím located in SC. My crawl space has an excess of moisture, as evidenced by white and black spore growth and moisture measurements of the wood and insulation. A contractor advised an encapsulation, to the tune of $24K. Are there less expensive options?
 
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Old 05-31-24, 09:01 AM
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A start would be to cover the ground with plastic sheeting. Can you increase the ventilation?
 
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Old 05-31-24, 09:23 AM
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With my rental properties I covered the crawl space floor with sheet plastic like MarkSr mentioned. Long ago the recommendation was to cover about 80% of the crawl space floor but I found it best to cover the entire area. Remove any debris that can cut or puncture the plastic. Then spread out 6 mil plastic, color doesn't matter.

And, make sure your foundation vents are open. Current code requires a lot more crawl space ventilation than what most older homes have. You can consider adding additional vents. Generally it's as simple as cutting holes in your foundation walls so how hard the job is depends on how your foundation walls are constructed. Vents work best when they are paced all around the crawl space perimeter so you can get cross or flow through ventilation no matter the wind direction.

And there are vent fans you can add to further increase ventilation. Most of them are available with temperature and humidity sensors so the fan only runs when needed but you do need to have power available so you may have to add an outlet or circuit for the fan(s). Any outlet in the crawl space must be GFCI protected.
 
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Old 06-03-24, 07:03 AM
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Thank you for your response. Given that there is mold growing (white and black spores), do I need a protective suit and breathing apparatus to go in and install the plastic sheeting?
 
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Old 06-03-24, 07:29 AM
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It depends on how sensitive you are. Most people don't need anything.
 
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Old 06-03-24, 09:08 AM
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Never hurts to at least wear a mask.
 
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Old 06-03-24, 10:32 AM
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Plastic sheeting is your best first step. Run it a few inches up each wall and tape the plastic to the piers.
I had same problem in So. Virginia. I got great results by sealing the crawlspace and running a dehumidifier.
You can spray the moldy areas with RMR-86, but you will need to wear a respirator.
 
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Old 06-03-24, 12:54 PM
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Crawlspaces are either vented to the outside and sealed from the house air or sealed from the outside and open to the conditioned air of the house. In the former, the insulation is on the ceiling of the space and on the walls in the latter. The biggest reason for encapsulation, IMO, is making the space part of the house air means you are now heating it in the winter, which makes the floor above warmer. As a result, you find that option more often the further north you go. Start thinking about all the details like having to remediate any of the mold and change how the space is insulated and you can start to see how it's such an expensive option. As stated by others, either way there needs to be a moisture barrier on the floor of the space.
 
 

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