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Old 05-29-2011, 09:38 AM
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My basement has taken water a week or so ago. While most of the water is gone, it is still humid, but cool down in the basement. Does a humid, damp basement affect the upstairs living space?

Right now, its about 68 degrees outside with 87 % humidity. Inside its 73 degrees with humidity over 75 percent. Is this normal? Could some of the high humidity levels be coming from my basement, or is it because of something else like poor wall insulation, air leaks to outside, not efficient enough windows?

Ive only lived in the home a year, and its my first home.

I did recently get a dehumidifier for the basement, a Santa Fe Classic. However, something may be wrong with it as it turns on even when I have it set to only turn on when the humidity is over 90 percent. And my Accurate meter says its only in the 60 humidity range down in the basement.
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Old 05-30-2011, 03:01 AM
Location: Florida
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I'd guess your meter isn't working well if the basement is noticably damp and the reading is 60%
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Old 05-30-2011, 06:32 AM
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Originally Posted by old_cold View Post
I'd guess your meter isn't working well if the basement is noticably damp and the reading is 60%

True but while I know it is damp down there, it isnt as damp as Ive seen it, which will come in the really hot days to come. There is still some damp spots from the water that came in from the rain a while back. I am going to call the maker of the Santa Fe Classic on Tuesday and ask them about it.

But my main question is, does the basement humidity affect the upstairs humidity? The temperature in here on the main floor is "comfortable" at 73 degrees right now, but the humidity is over 70. I dont think that is normal. Its not hot enough to turn on my central air, and that does help drop the humidity levels. But Id like to know why its so humid in here in the first place. If its coming up from the basement, I can understand that. Im actually planning some work im going to do to get an interior drain installed in the basement which I think will help down there.
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Old 05-30-2011, 06:37 AM
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I can say this much:

When I took up my hardwood floor to lay down new flooring, all that was between me and my crawlspace (at the time, outside temps were 90° and high humidity) was the subfloor (about 3/4 inch thick plywood). My house was hot and humid until I put down the vapor barrier and the flooring.

So yes, I'd say that basement conditions can affect your other living spaces, but can be mitigated by insulation. If you have a humidity problem, insulation might not be your answer though.
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Old 05-30-2011, 07:12 AM
Location: Johns Creek, GA
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Think of your house as a passive air movement device. When hot air rises it pulls the lower (basement) cool air up. That in turns pulls outside air in through every little crack, crevice, and penetration you have in the floor or walls- and yes, doors and windows constitute penetrations.
The only way to truly mitigate the problem is to eliminate or drastically reduce the amount of moisture that is getting in the basement.
It could be something as simple as gutters. Or extensions on downspouts if you have gutters. To more complex issues such as regrading the perimeter of the house, reducing the amount of concentrated run-off, or changing from concentrated flow to sheet flow. And the deepest wallet crusher- dig out the foundation, waterproof and add a new perimeter drain tile system.
Insulation in itself will have no bearing on mitigating your humidity problem in the conditioned spaces of your house- only sealing up every possible avenue in which air/moisture can travel will do that.
If the floor of the conditioned space (ceiling of the basement) isn't insulated- you don't have a complete "building envelope" of the conditioned space. That make for poor energy efficiency and wasted dollars.
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Old 05-30-2011, 08:04 AM
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Thanks for the replies. I do have old hardwood flooring in the home. As far as I can tell, no vapor barrier and no insulation in the attic ceiling.

Im assuming the vapor barrier should go on the ceiling side of the basement. I will look in to that. Ive also started working on the outside. Ive cleaned out the gutters and extended some of the spout drains. I want to work on the grading around the house, particularly in the problem spots above where I know water has entered the basement. Im going to add clay dirt grading to one area but the basement windows will be an issue. I take it, Ill have to put in window wells.

Other areas around the home that I know Ive got issue will be more difficult. One corner in the front of the house has worn asphalt. Not much I can do about grading though perhaps redoing the asphalt and ceiling it will help?

Also, in the back, they have more asphalt (not sure why, I wish it wasnt alsphalt). Old asphalt that is in rough shape that just puddles water. Around the storm walk out door there is also asphalt and Ive gotten water leaking down underneath the stairs to the basement. So for the asphalt areas and around the storm door, Im not sure what the best solution is.
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Old 05-31-2011, 05:53 AM
Location: Atlanta, GA
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70% humidity in your house is really high...is this with A/C running? I live in ultra-humid Georgia and keep one of those temp/humidistats in my house to monitor, and we maintain 45% or less even now when it is 90's and mega-humid outside. We are on a dirt crawlspace and had issues when we had new hardwoods installed b/c the humidity from the crawl was transferring up through the floors into the cooler house, thus leading to floor cupping. We encapsulated the crawl and have a dehumidifier put down there keeping it 40-50% and the floors went back to flat and seem okay now. Just saying that, yes, basement humidity WILL transfer up into the house, as that is how the building envelope works as everything flows up and out the roof from an air perspective.
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Old 05-31-2011, 09:02 AM
Location: CT - USA
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Yes, as K'ledge said, because of the way air moves inside the building, the air and humidity in the basement is definitely getting upstairs. Hot air rises, escapes through the roof, more air is sucked it through the basement and crawl spaces (the lowest levels of the house, which have the highest level of negative pressure) . We call that the "stack effect".
Because of it 1/3 of the air you breathe in your home at any given time, is coming from the basement. Along with mold and humidity.

Now you do have a very good dehumidifier down there, so the dehumidifier is not the problem. The problem is that a dehumidifier ONLY addresses moisture that is evaporated into the basement. But the bulk of the moisture is coming from your basement walls and floor. It is ground water seeping through the concrete, which is very porous, and a dehumidifier alone won't help it.

What you need to do is to take ever necessary step to prevent that soil around the house to get saturated with water. Cleaning gutters (or installing), extending downspouts, grading the terrain to slope away from the foundation and keeping plants that need constant watering as far from the house as possible, helps.

If the dampness persists, consider installing an internal perimeter drainage system, with a sump pump. This system will collect ground water and discharge it away from the foundation, thus relieving the hydrostatic pressure that is pushing all that moisture against your basement walls.
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Old 06-03-2011, 01:36 PM
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Most of the posts here are right on point. You have a very capable dehumidifier, but it may not be able to keep up with the amount of water entering your basement. You need to address the liquid water entering your basement before the dehumidifier can address the water vapor in your basement.

70%rh is too high inside your house. This high level of water vapor will lead to mold and mildew growth in your house. Water vapor will move from the basement into the upper parts of the house, so it is difficult to keep one part of the house dry while leaving another part of the house wet. Be careful installing water vapor barriers as you can create condensation on the wet side of them leading to mold problems as well.

Get your gutters and downspouts carrying water away from your basement during rains. Grade the earth around your house so water runs away from the basement. Asphalt, concrete and other hardscapes may be mudjacked or removed to grade away from your basement. You do not need much grade - google basement grade for advice. You may need to install a basement sump and pump to control the water, but I would not do this until I have the grading and roof drainage working to see if it is necessary.

Air infiltration from outdoors is the next issue the leads to excess moisture in your house. You want to seal cracks and openings in your walls, doors, and windows. Check your sill plate (board that sits on top of the concrete basement wall) and band joists (board that forms the wall at the end on your floor joists) for cracks and openings.

Many of these items can be addressed as a DIY project without incurring a large expanse if you are pinching pennies. Or you can hire a competent contractor to fix your landscaping and basement.
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Old 06-03-2011, 04:23 PM
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Please call Todd at 800-533-7533 ext. 8401 and let me know if you still have any questions about your Santa Fe Classic dehumidifier. (I work for Therma-Stor, the manufacturer of your Santa Fe dehumidifier.)

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