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Letting a little moisture stay in crawlspace?


CharlotteAnn's Avatar
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04-12-06, 02:38 PM   #1  
Letting a little moisture stay in crawlspace?

We had 6 mil poly installed in our crawlspace today. The people who installed the plastic left a little ground exposed in small areas. They said that some moisture actually needs to be present or it would actually get too dry and crack the floor joists and affect hardwood flooring. Our home is 17 years old. Does this sound reasonable? (We do have a B-Dry water drain system in the crawl space.)

 
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04-12-06, 03:13 PM   #2  
I am not the expert in this Forum but everything I have read says to overlap the poly by about 1 foot and tape the seams. It also states to go up the walls 1 foot and seal along the edges. I could not find anything about leaving holes to let moisture in. Thats why it is called a vapor BARRIER. Good luck.

 
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04-12-06, 06:56 PM   #3  
No Plastic should overlap!

 
Doug Aleshire's Avatar
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04-12-06, 08:13 PM   #4  
airman.1994,

Unfortuantely, you are wrong in saying "no plastic should overlap.."

Please read the following provided by the Dept. of Energy and is incorporated in the IRC 2003.

http://doityourself.com/info/vapordiffuseairbarri.htm

Note the section "Installing Vapor Diffusion Retarders".

Just want to set the facts straight. If in doubt, contact your local building official.

 
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04-13-06, 04:50 AM   #5  
Posted By: CharlotteAnn We had 6 mil poly installed in our crawlspace today. The people who installed the plastic left a little ground exposed in small areas. They said that some moisture actually needs to be present or it would actually get too dry and crack the floor joists and affect hardwood flooring. Our home is 17 years old. Does this sound reasonable? (We do have a B-Dry water drain system in the crawl space.)
Sounds like they ran out poly and gave you an interesting excuse. I hope you haven't paid them.

Moisture is controlled from the inside of the home by the use of humidifiers and de-humidiers. NOT by leaving holes in the vapour barrier.

This moisture could in fact cause rot damage to your floor joists.

 
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04-13-06, 05:31 AM   #6  
Posted By: Doug Aleshire airman.1994,

Unfortuantely, you are wrong in saying "no plastic should overlap.."

Please read the following provided by the Dept. of Energy and is incorporated in the IRC 2003.

http://doityourself.com/info/vapordiffuseairbarri.htm

Note the section "Installing Vapor Diffusion Retarders".

Just want to set the facts straight. If in doubt, contact your local building official.
Doug-

I think you misunderstood airman's post because he forgot a comma... I'm sure he probably meant "no, plastic should overlap".

 
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04-13-06, 05:37 AM   #7  
jganyard,

You know, after reading it again, I think you are right.

Sorry, airman.1994.

Thanks

 
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04-13-06, 06:12 PM   #8  
Opps Type O ,,,,,, Sorry guys!

 
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