Crawl Space Moisture

I have just moved into a new home and I have a problem with the moisture in the crawl space. I went into the crawl a month ago and the AC vents are slightly dripping. This dripping is causing puddles on the plastic that is covering the floor of the crawl. Mold has started to grow.
The builder was notified and they removed all of the plastic from the crawl space. The plastic will be replaced in a month because they believe the moisture is from the wet summer we have had this year. They also mentioned putting in crawl space fans to help move the air down there so the moisture won't build up.
Now, this is my take on things. I think the vent lines should be better insulated so they won't condensate. I'm also not sure about having the vents opened all summer and closing them in the winter. Everyone seems to have a different opinion on this.
The last thing I want is mold, termites and rotting wood in my nice new home.
Does anyone have any suggestion or experiences? I would appreciate anything because this is our first home with a crawl.
Thanks. CG
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Insulating your ductwork would solve condensation problems and save you on utilities. Vents open all summer ? heating or exterior wall vents ? A fan to circulate moist air? It sounds like you have several problems, Call your Bldg inspector for free onsite advise, I wouldnt trust the builder who cut corners on your ductwork and recomends a fan.
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Mark -
Thanks for the reply.
I have been told, by several people, to leave the vents open all summer and the close in the winter. So, my vents are wide open. They are exterior wall vents.
The builder does want to install fans. I'm not sure what kind yet, but I am going to find out.

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It sounds like the vents are too small. They should be open all the time winter and summer.
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Joseph E. Meehan

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You might want to make sure your gutters are in shape and working properly. I've seen the house with cracked and bent gutter creating water puddle at the vent. Water went in to the crawling space and created a little pool. The problem was left alone for years, and then one side of the house started sinking in to the mud. Now none of door can be shut because of uneven floor, then ceiling got crack.. Every thing is because of the gutter.

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I have the same problem.
I have decided to put down the plastic and attach it to the walls. I plan to put rigid foam on all the crawl space walls. I will then remove the floor insulation. I have closed and sealed all my vents. They just let in more humid moist air all the time here in North Carolina in the summer. I have put a dehumidifier under the floor to get everything dried out. I am running it non stop right now but when I get everything sealed and dried I think I can set it so it only comes on occasionally. I may also open one of the AC ducts to allow cool dehumidified air to flow into the crawl space. When I am finished it will be more like a basement instead of a crawl space.
The requirement to ventilate the crawl space is based on research done in the 40's before homes were air conditioned. I put a bunch of links on a web page so I would not lose them. The recent research indicates that ventilating a crawl space during hot humid summers is the worst thing you can do.
www.bobbystuff.com
Bobby

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