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I was under a house doing some electrical work and saw more moisture than I have ever seen. It has been raining a lot every day for a week or more here in central VA. The crawlspace has plastic on the dirt floor, and the underside of the plastic is dry. The top of the plastic in covered in condensation and ciollecting in puddles. I looked up, and the fiberglass floor insulation also has condensation on it! Drops of water everywhere.
I suggested he close up the vents and run a dehumidifier, draining outside of the crawlspace. Did I advise correctly? Any other ideas?
Frank
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Good idea to get rid of the existing moisture, but the long term fix could be more complicated. First, check the gutters--#1 source of crawl water, then grading around the house, it must slope away. Good vapor barrier on the ground and venting is next. They may need a power vent on a humidistat. Any chance a pipe is leaking? Check the water meter for flow with everything off in the house. Keep at it the water will wreck the house in no time starting with the paint and hardwood floors.
*Thanks for the reply Tom.The gutters were replaced recently with more downspouts than I have seen, like 3 per house side on a hip roof. They drain underground and downhill from the house on the back side. I'll look again at the front side and make sure the drains are still open.The crawlspace has a vapor barrier in place, the floor is covered in plastic film. Under the plastic film is dry dirt. Friday when I was there finishing the HVAC move, the moisture was less, and so was the outside humidity. I got a good look at the plumbing, as he wants to move a hot water heater, and nothing is leaking at this time. Frank
*Frank,It sounds as if the primary source is either a plumbing leak or hot humid outside air hitting cool surfaces.I think your advice was right on. See if they can borrow a dehumidifier to get it dried out, and then see if keeping the vents closed will keep it dry without the dehumidifier. Monitor the situation, though.Steve
*Frank - sounds like it was outside air condensing inside the crawl.The dry dirt underneath is a very good sign.Now you have to get the wet insualtion out of there and let the floor joists dry out before you reinsulate.A fan and humidistat will NEVER solve this problem in your area. Unless maybe if the house is on some sort of geothermal vent and continually gets 100 dgeree air at 100% humidity.-Rob
*Frank, down here in Williamsburg, I've seen moisture condense on the HVAC ductwork and drip into puddles on the poly barrier. This time of year is when it starts to show up... AC running regularly and lots of humidity. You mention that there was LESS condensation when you went back in the finish the HVAC work... by any chance was the AC inoperative for a day or two before that visit? That could account for the sudden decrease in condensation.A lot of the problems I've seen could be solved with better ductwork insulation and sealing, which I feel is critical regardless of whether the crawl space is vented/unvented/dehumidified/whatever.Humidly, Steve
*Steve, the AC has not been working for a month, that's why I was surprised at the ammount of condensation without the AC running to cool the ducts and leak cold air. I think it was less recently due to lower outside humidity. Now I have the AC running again, I shall go back and see if the condensation on the duct work has increased.Rob, I think outside air also is the problem here. I haven't seen any geothermal steam rising from cracks in the earth.The homeowner has not placed the dehumidifier in the crawl yet. I'll keep after him.Thanks,Frank
*Standard practice here in Arkansas is to vent the crawlspace in summer and close it up in winter. The discussions here at Breaktime have made me acutely aware of this. When I tell folks that I plan to block the vents of the house I'm building I get strange looks. But then I ask, "Do we really want to put all this hot, humid air into our crawlspace so it can condense on everything in sight?" And of course, they've never thought of this before, but reply, "Well, no." (It's that obvious.) I intend to use everything I've learned to create "the perfect crawlspace" (yea, right) which will be a shining example of common sense over tradition. OK, maybe not, but it'll be interesting.