Basement humidity solutions?


  #1  
Old 05-16-03, 10:16 AM
ryancramer
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Basement humidity solutions?

I have a 1930s bungalow that has a high level of humidity in the basement/crawl space. The basement is mostly earth except for a 20x15ft area of concrete floor where the utilities are. There are several foundation vents around the perimeter of the house, though I've never exactly felt a breeze down there. I'm concerned about the wood structure (joists, subfloor, etc) as high humidity can't be good for it, I've also noticed some small patches of mold in some joists, though there doesn't appear to be any rot or infestation (yet).

What would be a good way to proceed with this? I am looking at the following options:

1. Adding an exhaust fan on one of the vents to increase airflow.

2. Put in a dehumidifier

3. Put down 6mil polyethylene sheeting over all exposed earth areas.

4. Stop worrying about it. After all, this house has survived this long without any solution, maybe its just supposed to be like this?

The area that I live in (Atlanta) has very high humidity outdoors, so I was worried that installing an exhaust fan on one of the vents might in fact draw in *more* humidity?

I like the dehumidifier idea, but wonder how effective it would be since there are foundation vents? Like I said, I don't feel a lot of ventilation going on down there, but there must be some (it doesn't smell bad). Furthermore, I would have concerns about blocking up the vents as it would then confine any radon or other gases into the house. Should I buy a dehumidifier?

Laying down the 6 mil poly seems like a good idea, but our inspector (when we bought the house) said it would not be necessary in this case (why, i'm not sure).

Any advice or suggestions would be greatly appreciated.

thanks,

Ryan
 
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Old 05-16-03, 12:42 PM
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humidity

As long as you have exposed earth in your basement, you will always have a humidity problem/issue. At a minimum, if you cover the earth, you will minimize moisture intrusion from below. As for outside the home, think about downspouts and gutters and make sure they're clearly draining AWAY from the foundation. A dehumidifier will help, but with exposed earth, you'll have to dry out the greater Fulton County area before you get all the moisture 'out'. Best bet would be to put down a slab in the basement. Roll of Plastic (4mil) = $15, Dehumidifier =$100-$200. Concrete = $100+/yard in my area. Use a combination of all three and you'll be in good shape.

This is also contingent on WHAT you want to do in the basement (i.e., how much you want to spend)

Good luck
pat
 
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Old 05-16-03, 01:22 PM
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humidity

As long as you have exposed earth in your basement, you will always have a humidity problem/issue. At a minimum, if you cover the earth, you will minimize moisture intrusion from below. As for outside the home, think about downspouts and gutters and make sure they're clearly draining AWAY from the foundation. A dehumidifier will help, but with exposed earth, you'll have to dry out the greater Fulton County area before you get all the moisture 'out'. Best bet would be to put down a slab in the basement. Roll of Plastic (4mil) = $15, Dehumidifier =$100-$200. Concrete = $100+/yard in my area. Use a combination of all three and you'll be in good shape.

This is also contingent on WHAT you want to do in the basement (i.e., how much you want to spend)

Good luck
pat
 
  #4  
Old 05-16-03, 02:44 PM
ryancramer
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Thanks for the reply. The basement isn't really a usable space, other than for the utilities. I might like to put a work bench in there or something, but otherwise my only interest is in keeping the environment healthy and preventing any further wood rot. I'm going to follow your advice and install the poly sheeting over the dirt areas to start with--this is going to be a big project.

thanks,
Ryan
 
  #5  
Old 05-20-03, 04:54 PM
indigo997
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This is my problem with my bungalow as well!
Have you found any specific information on installing the plastic vapor barrier? I don't mind getting dirty and doing it myself, but I'd like some tips on exactly what to do. My basement tends to get wet (especially with the flooding we've had lately). How much should the plastic overlap and what do you use to hold it in place?

I was also told to keep the basement entry door open to the outside in dry weather to allow more air exchange.
 
  #6  
Old 05-21-03, 05:45 AM
ryancramer
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I haven't found any specific information other than basic stuff, but what I know so far is that its best to use 6mil black poly. They are selling this stuff at Home DePot in the paint section for $25 per 100x25 feet. I've heard that when you put it down, its good to overlap it by a foot or two, and to tack it down with rocks, bricks or gravel. Getting around brick piers and such sounds like its giong to be a challenge. I'm not looking forward to this project, but I think it'll be worth it. Let me know if you hear anything else on how to do this?
thanks
Ryan
 
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Old 05-21-03, 11:35 AM
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Crawl ways

On crawl ways we put down the 6 mil poly. over lape it 12 " and up the wall 12" duct tape the over laps. put a 2" polystyrene on the walls up to the floor joist. put a R19 insulation in the joist space there on the sill plate all around the home. cCose all vents. Run a dehumidifier will sure help. To open that door will just let warm humid air in on the cooler ground and it will all get wet again. Go over to

Http://www.taunton.com/finehomesbuil...ges/h00107.asp

This can give you some ideas ED
 

Last edited by Ed Imeduc; 05-21-03 at 12:51 PM.
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Old 05-21-03, 12:27 PM
ryancramer
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Ed,

Thank you for the reply. I couldn't get the link to work at first, I think a slash was missing, but this URL seems to work:

http://www.taunton.com/finehomebuild...ges/h00107.asp

That article was very helpful--thank you again for posting that, its exactly what I needed.

Ryan
 
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Old 05-21-03, 01:03 PM
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crawl way

One more if you want it

http://www.ornl.gov/roofs+walls/


hit on the hand book and fact sheet

ED
 
 

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