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I was looking for some advice about our crawl space. We have been in our current home for almost 3 years and never had high moisture in our crawl space except for the last year. We had an issue with some of the gutters last summer that allowed water from the roof to fall by the foundation that we didn't notice for a while. Then when we got that fixed, it caused another problem that we fixed this spring. As far as we know, we have fixed the source of the moisture. It is not muddy in there, but the top of the spoil is clearly damp. We noticed our supply duct from the HVAC had some condensation this summer, too. We are assuming this is all from the excess moisture.
Anyway, we would like to put a vapor barrier down, but I was wondering if we should do this after getting rid of some of the moisture. Should we get a cheap humidifier (any recommendations?) and put it down there for a while before putting the vapor barrier down? We want to do a good job with the barrier (overlap pieces by a foot, seal with tape, bring partially up the walls), so if it is pretty moisture impermeable, I am wondering if laying it down before drying it out will prevent us from being able to remove a lot of the moisture with a DH??
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You could have condensation on your ductwork just because of the humidity in the air.
Your foundation vents allow the moisture-laden outside air in and the cool ductwork creates condensation.
Some folks say you should close off the vents and completely seal your crawlspace to keep the ambient air out.
If you put down a simple vapor barrier, there is no need to let the ground dry completely. The function of the simple, traditional vapor barrier is to cover about 80%--85% of the ground surface and to control the amount of moisture emanating into the air, so that controlled amount will be ventilated out the crawlspace vents.
If you want to completely encapsulate the crawlspace, and eliminate the vents, be certain to allow inspection clearance at the foundation walls for your termite control company. That is one of their concerns, that you will obscure the visibility of termite presence and have an unnoticed infestation in your home.
You might want to look at how they do a moisture barrier for a mobile home that has a skirt. During alot of the year IMO its a mistake npot to have opening for air flow in a crawl space. Its a sure way of having mositure problems that can get thru most flooring into your house. Moisture can even eventually go thru concrete.
First you should ensure the area has good drainage and no further moisture will enter the enter area and soak the soil.
Soil is always going to have some moisture below the top few inches. I would just put down some plastic tarp as a continuous layer as much as possible. Once the soil layer is covered no more moisture can get into the air from it. Don't worry about what is already there.
I don't like the idea of just covering the soil. Put in a thin layer of fine pea gravel first, roll that down good. Gives a good firm base, if you are in there in the future. Then I like a plastic tarp, then some dry sand, another layer of plastic tarp. Some folks with mobile homes put dry leaves into plastic bags and make a layer of them on top of the last sheet of plastic.
The soil can never freeze, eliminates frost heaves and helps keep the entire area under there warmer. Regular plastic sheeting gets brittle and breaks up over time, if you ever have to go under there punches holes. The plastic tarps are much stronger. Can use some plastic sheeting under the last tarp layer. More layers are better. They make huge plastic tarp sizes, should not have to cut much, can just fold them to fit.
Certain duct insulation becomes useless after becoming wet. It's insulating properties are shot. Do as the others said and fix those issues like drainage, the gutters, vapor barrier and then you might want to think about having someone come check out the insulation on your duct work. The last thing you want it to cool the crawl space or heat it. I happen to have first hand experience with this as my parents house had practically the same issues you do. they have a package unit and that means lots and lots and lots of duct work. Practically all of it sweated a few years back before the proper venting was installed. Now the HVAC ducts still sweat because the temperature of the duct work is almost always under the dew point where they live and the insulation is worthless. I have other things I need to fix there also and since I'm unemployed I have all sorts of time now...
Fiberglass is not quite as problematic when it gets wet since it's absorbed into the insulation. Fibrous types are because they tend to compressor when they get wet:
Quote:
When fiberglass insulation becomes wet with water, such as most rain and/or supply water, it will temporarily lose a substantial measure of its thermal resistance (R-value). In this case the spaces between the fibers that were previously occupied by air are now occupied by water. Since water is a much better conductor of heat than air, the water presence would cause the insulation to have reduced thermal performance. However, this is only a temporary situation. As soon as the water evaporates and the insulation becomes dry again, it will regain its original performance level.
In addition, since fiberglass insulation does not absorb water, the insulation fibers will not be structurally altered or permanently affected in any other way. The material will essentially be as good as new after it becomes dry, provided it has not lost thickness.
This thread is almost 6months old-
And I have no idea how a company in London, England; UK is going to help someone in NC; USA.
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Correct any drainage problems right
good luck
