# Plastic under house in crawlspace?

**URL:** <https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270>\
**Category:** Factual Questions\
**Created:** [November 4, 2002, 11:11pm UTC](https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270 "2002-11-04T23:11:19Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![galyean](https://avatars.discourse-cdn.com/v4/letter/g/f9ae1b/32.png) [@galyean](https://boards.straightdope.com/u/galyean)\
**Post date:** [November 4, 2002, 11:11pm UTC](https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270/1 "2002-11-04T23:11:19Z")

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Is there any value in putting plastic down underneath your home? Does it eliminate or reduce exposure to insects or termites? Is it supposed to prevent water vapor from rising up to the joists and subfloor?

I have it and it seems to be more of a nuisance. I don’t mind crawling around on the dirt, but I have to retidy or fix the plastic because it moves every time I slither across it.

Remove it or leave it?

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [November 5, 2002, 12:36am UTC](https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270/2 "2002-11-05T00:36:36Z")

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I don’t know but want to

Perhaps it’s to prevent moisture from comming up through the ground

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**Author:** ![Yeah](https://avatars.discourse-cdn.com/v4/letter/y/dbc845/32.png) [@Yeah](https://boards.straightdope.com/u/Yeah)\
**Post date:** [November 5, 2002, 1:06am UTC](https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270/3 "2002-11-05T01:06:43Z")

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It is to prevent moisture from coming up through the ground but I’m not sure that much moisture comes up out of the ground under a house. Does anyone have any data?

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [November 5, 2002, 3:59am UTC](https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270/4 "2002-11-05T03:59:05Z")

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Are you ever going to **sell** the house ?

> [@](#):
>
> As part of my FHA closing I need to get a crawl space vapor barrier insalled. This is in a 115 year old home with a combination of basement and crawl space.

-[bobvila](http://www.bobvila.com/wwwboard/messages/48478.html)

I’m not sure what the rules are but this google on [“Crawlspace Vapor Barrier”](http://www.google.com/search?as_q=&num=10&hl=en&ie=ISO-8859-1&btnG=Google+Search&as_epq=crawlspace+vapor+barrier&as_oq=&as_eq=&lr=&as_ft=i&as_filetype=&as_qdr=all&as_occt=any&as_dt=i&as_sitesearch=&safe=off) can probably tell you.

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [November 5, 2002, 4:27am UTC](https://boards.straightdope.com/t/plastic-under-house-in-crawlspace/135270/5 "2002-11-05T04:27:05Z")

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I had a bunch of dew/water collecting on the attic trusses and falling all over stored possessions until I put the plastic vapor barrier down. They work if you have a lot of moisture in the soil that is being trapped in the house.