Can't get moisture down in basement

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  #1  
Old 07-03-12, 06:59 PM
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Can't get moisture down in basement

For the life of me I can't get the moisture level of my basement down below 60%. I've got a dehumidifier running down there but it doesn't seem to be working. I've tried checking the basement floor and walls for moisture and it doesn't look as though it's getting in anywhere.
 
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  #2  
Old 07-03-12, 07:10 PM
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How's your drainage away from the foundation from the downspouts? Is the floor concrete? Have you taped a clear piece of plastic down and left if for a couple of days to see if any moisture is eking it's way up from the concrete? Is it a walkout or all below grade?
 
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Old 07-03-12, 07:50 PM
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One side is a walkout, and the humidity there is at 40%. The other side is completely below grade. THe basement looks like a long L and the one side is 40% and the other side is 60%. I've taped some plastic and I don't see any moisture seeping in.
 
  #4  
Old 07-04-12, 04:21 AM
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You won't see any moisture seeping in because it is water vapor. How big is the basement and how big is your dehumidifier? What is the temperature in the basement? What is the age of the home?
 
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Old 07-04-12, 05:26 AM
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Forgot to ask, too, does the basement have conditioned air?
 
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Old 07-04-12, 09:48 AM
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The basement has a heater. The home was made in 1969 and it looks like nothing is seeping in. It was sealed with that latex sealer at some point. It's big, something like 1500 square feet. One side sits around 45% humidity, the other is the one that's sitting around 60%. I've been running the air down there for nearly a week now, alongside the dehumidifiers. I'm not sure about the temperature, but it's cool. I'm just outside of Atlanta.
 
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Old 07-04-12, 11:37 AM
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I'm just outside of Atlanta.
Me too, waaaayyyy far outside. You say you are running the "air" down there. Is it conditioned air? Is there a return duct to the system from down there?
 
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Old 07-04-12, 01:25 PM
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What size is your dehumidifier? Do you have more than one? Put as thermometer down there. The cooler the air, the harder it is to remove water vapor from it. The ratings on the dehumidifiers are based on running them at around 85 degrees. Lower temps will yield less water than the stated rating.
 
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Old 07-05-12, 04:15 AM
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With two dehumidifiers I can get it down in the 40s but I can't sustain that down there. How do I keep moisture out? Should I reseal the place? How would I check for moisture other than sticking a hygrometer down there?
 
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Old 07-05-12, 05:41 AM
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It sound like your dehumidifier is not big enough for the space.

Please respond back with the size/capacity of your unit and the temperature in the basement.
 
  #11  
Old 07-05-12, 02:01 PM
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With two dehumidifiers I can get it down in the 40s but I can't sustain that down there.
What do you mean you can't sustain it?
 
  #12  
Old 07-05-12, 07:49 PM
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ive got a mushroom farm which i need too control the humidity in there constantly, but at a much higher range 85-90%, like it is here now in Australia,, Winter, it drops too 0 deg celcisus here often, with the huge amount of fog we have as well, it makes it hard too remove the moisture, so i just simply use a small ceramic tower heater, i set it too 19 deg?C, and it rips the excess moisture out of the air very quick, if i leave it on too long it takes way too much moisture and drops the R/H too under 50% with out a problem in a few hrs,with vents closed off, i also use too suffer from bad moisture in a basement, i tried putting in venting fans alone too solve this problem, but it only partially helped, so i was advised too either use a small oil type heater or fan ceramic style, and run it at about 18-20deg/C, and not too run the exhaust fan unless it was sunny out side and never in the winter nights or rainy days or nights, i used/use the heaters with LED control for setting required temps, so as i can keep the rooms at a certian temp and not get too hot, i also tried and have large Dehumidifiers, 58L and 90L per day, but i can tell you from experience the heaters in a room with no ventilation will work much faster for you than a dehumidifier will, and the larger dehumidifiers will chew up more power than a small room heater set on a timer, or even too a dehumidifier controller, which will switch the heater on and off when it reaches desired levels, you can buy these on ebay for under $50, eBay Australia: Buy new & used fashion, electronics & home d here is the link for them, and 18-20 Deg/C is a comfertable temp range for most things, hope this helps you out
 

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  #13  
Old 07-06-12, 08:10 PM
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When I say sustain, I can't keep the humidity down. I've got two hygrometers, one is saying it's 60% the other says 70%. Granted, it just rained here about an hour ago. It's 80 in the basement right now, but considering the heatwave and the fact that the rest of my house is around 90.....

The main reason for this is because I had a mold problem in this side of the basement. The other side's humidity seems to sit around 50% regardless of what I do. I tried taping down a piece of plastic and I don't see any condensation there, ditto for the walls. There's a sump pump in the corner and a drain in the center of the floor. I've got air circulating down there running through a HEPA filter to get the mold out of the air. There was a problem with penecillius mold and we demo'd all the insulation and drywall down there. It knocked it down but not low enough...hence why I'm running the HEPA filter. I had the place remediated and it looks like i'm going to have to do it again shortly. THis tiem with the air filtration running.
 
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Old 07-06-12, 10:08 PM
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I'd first make sure your RH gauge is calibrated. 2nd I look into a good unit like a Santa Fa twice the capacity at half the energy used plus low temp.
 
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Old 07-07-12, 06:09 PM
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How do I calibrate it? Can you elaborate as to what a Santa Fa is?
 
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Old 07-07-12, 06:29 PM
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He means Santa Fe. They are a dehumidifier manufacturer. Are you running your dehumidifiers around the clock?

When you say it is 80 in the basement right now, do you mean 80 degrees or 80%?
 
  #17  
Old 07-08-12, 06:36 PM
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The haier is about the size of one of those single room freestanding ac units. It's got a 1-2 gallon capacity. The other one vents outside. It looks like an elongated space heater.
 
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Old 07-08-12, 06:39 PM
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Oh I meant 80 degrees. I flipped the units off this morning when the humidity there was 50% on one and 70% on the other hygrometer. Let it sit for 6 hours. The first unit read just under 60% and the other just under 80.
 
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Old 07-10-12, 04:06 AM
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Anybody? I tried switching off EVERYTHING and get a humidity of about 50%.
 
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Old 07-10-12, 09:23 AM
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Oh, and I forgot to add, I am running them continuously.
 
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Old 07-10-12, 01:20 PM
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You've got 80 degree temp in a below grade basement?? How many windows? Again, you said you are running air down there, is it conditioned air, or the air in the hepa, and is there a return to the house system?
 
  #22  
Old 07-10-12, 01:40 PM
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The other one vents outside. It looks like an elongated space heater.
The unit you described. How does it work? Is it just a fan that takes air out of the basement and puts it outside?
 
  #23  
Old 07-10-12, 04:44 PM
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I'm running air but it's not conditioned, it's just running through a HEPA filter. The former owners had a heater for the basement but not an AC. The Haier unit has a collector for water. The other vents outside and I think is venting water outside. As far as windows go, I have a series of 7 1 square foot basement windows toward the top of the outside walls.

Also, since we're getting some heavy rain here in GA today, I was able to find out that the walls themselves leak. It looks like sealing the basement is in order. Not to change the topic, but what is recommended for sealing? Latex sealer?
 
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Old 07-10-12, 06:37 PM
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Sealing basement walls is done from the outside with grading, gutters and downspout extensions keeping the water away from the walls in the first place, not by painting the inside surface.
 
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Old 07-11-12, 03:57 AM
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I understand. What is the best course of action for me in this case then?
 
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Old 11-02-12, 01:12 PM
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Well I had a structural engineer come in and look at things. I'm getting french drains and vapor barriers put in the entire basement. I'm told this will get teh moisture down with all the built up water out there.
 
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Old 11-06-12, 01:51 PM
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Hi folks. I wanted to update this thread and hopefully get a little more advise.

I'm finally getting Sundry waterproofing to come in. They're going to go ahead and put french drains all the way around the basement and put vapor barriers up all the way around as well. What I'd like to know is, will I need a dehumidifier after this? If so, is there a recommendation? I saw one mention of Santa Fe, if that is the best unit I'm comfortable getting one of those.
 
  #28  
Old 11-09-12, 12:57 PM
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I have a Santa Fe ("Classic" I think it is) and I have to say its one of the best investments Ive made for the house.

My basement is open to my first floor and the Santa Fe actually helps take the humidity out of there too. I can get my basement down to below 40% if I really want, and thats with the dehum on the unfinished side and the controlling humidistat on the finished side with only a doorway separating them. I just aim to keep it around 45% or so, below 50 is fine in my book. I dont usually have a huge moisture issue in my basement, but I think the Santa Fe unit is big enough to at least help your issue. It is completely different than any other "box store" dehum Ive had. Its quieter, much more efficient, and actually does what it says it will.
 
  #29  
Old 04-25-13, 05:29 AM
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Well folks...I got to the root of the problem.

I laid out a bunch of hygrometers and plotted the moisture levels...guess where they're highest. Around my sump pit. Last weekend the wife and I put plastic sheeting down covering the lid of the sump pit and the humidity in that area, which was the highest, dropped down below 40% in under an hour. This leads me to believe that my sump pit is the problem here.

Are there any suggestions for keeping the moisture in the sump pit? There's a cover on there now. This plastic is in addition to that.
 
  #30  
Old 04-25-13, 06:37 AM
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Hi diy,
Good investigating. Be sure to measure temperature at the same time and use one of the calculators to adjust the RH of all readings to one temperature.

Sump pits have two functions and being open covers both, ground water and water on the basement floor. If your floor is currently dry, then covering the pit will eliminate the direct evaporation from the exposed water. But it creates a problem that a broken pipe may flood the basement without the sump pump being able to help.

One home owner I know created a floating lid that would cover the pit when the basement was dry, but if needed, the lid would rise with the flood and go to work at least keeping the water down to the surface level.

I prefer a second deeper pit to try and lower the water level under the concrete floor. In fact several pits if you do not have a good gravel base under there. See how they work and then add another as an open pit sealed off from the water below, but open above in case a washer hose lets go or other pipe breaks. That's a lot of pits, but how many is up to you to decide.

As for the humidity, a dehumidifier is almost a necessity in the summer when outside warm humid air leaks in. Watch the outside dew point and then check your basement temperature. If you air condition, then research insulating the basement walls and condition the basement.

Bud
 
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Old 04-25-13, 12:05 PM
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Thanks. I'll have to look into that. I've never adjusted a hygrometer before. I'm starting to think that my digital ones are a little haywire because they never drop below 60% no matter where they are, even outside and the RH is in the 50s.

I don't think that I'll have any freestanding water in the basement, even from burst pipes. I've got a few floor drains that should stop that, even if there's a burst pipe. I do like the idea of having another pit.

What about the pump iteself? Should I really have that much water in there to begin with? Coming from a ranch house without a basement, I thought that those things kept the sump pits rather dry.
 
  #32  
Old 04-25-13, 12:22 PM
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Sump pumps and pits only provide a collection point to remove excess water. They only go dry when the source of that water is removed. Placing one lower into the ground may lower the water table by gathering the water before it accumulates to the floor level, but it does nothing to stop the flow of incoming water. landscaping, trenching and outside drainage away from the house is the cure. Unfortunately, not all homes are located where there is a downward area to send all of the water.

I had one where we had to install a huge dry well. The soil was all sand so once we directed all surface water to the chamber, it disappeared. In your case the water is not going away, but accumulating until it flows into your sump pit. It could be just your basement is dug into a hole that cannot drain, or the water table in the entire area. What's down there, ledge, clay, or a lake? It isn't easy to determine sometimes, but describe it and we will try to help.

Bud
 
  #33  
Old 04-25-13, 01:04 PM
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Unfortunately it's on the side of a hill and this corner is effectively in a hole. The cover on the top so far seems to be the best option.
 
  #34  
Old 04-25-13, 02:48 PM
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Are you along Nancy Creek? Just wondering as sump pits aren't that common except where ground water is high, and Atlanta is a higher elevation than surrounding areas.
 
  #35  
Old 04-25-13, 02:53 PM
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Atlanta is a slight misnomer. I'm actually in Marietta.
 
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Old 04-26-13, 07:12 AM
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Well, after 24 hours with no dehumidification or anything running, the humidity is just over 40%, which is around half what it is outside.
 
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