Crawlspace question?

Originally Posted By: tbramlett
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I was wondering if it is code for there to be a vapor barrier covering a dirt floor, or if it is just considered a good building principal. If it is code, can you tell me what the code is and how long it has been in effect. Thanks


Originally Posted By: five.five
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A couple of things I found in IRC, per code R408:


Ventilatoin openings are not required when the ground serface is covered with an approved vapor retarder material,…in accordance with section N1102.17


Can't really help you with how long the vapor barrier code has been in effect.


Hope this helps.


Originally Posted By: dvalley
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Tom,


As far as I know, there is no code that requires a polyethylene vapor barrier. It's just good building practice, as you said.
In Massachusetts, if this dirt floor is in a full basement, I always inform my client that the life expectancies of the mechanicals in this dirt area will be shortened greatly without a poured concrete floor or a vapor barrier. Dirt floors here are always moist. Everything tends to rust very rapidly, too include the internal parts of the SE panel. Also, if there are no signs of Powder Post Beetles in the beams, girders and posts, they got very lucky. 90% of dirt basements I inspect have these wood boring insects.

I see dirt crawls more than I do dirt basements. Even these crawls need attention. I always inform my client that dampness can ruin wood and cause structural problems and can also breed mold in living space if a (min. 5 or 6-mil) vapor barrier is not in place. Ventilation and insulation are also considered to be good building practice in crawl areas.

![](upload://BYoPsMI5k9iOZZDpFd3StGGioL.gif)


--
David Valley
MAB Member

Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."

Originally Posted By: rcloyd
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Given the proper number of code required ventilation openings, a crawl space does not have to have a vapor barrier. All vegetation must be removed from the underfloor space. Additionally, if the wood beams and joists are less than 18 inches above the dirt, they must be pressure preservratively treated.



Regards,


--
Russell G. Cloyd
Intra-Spec Home Inspections
& Code Consulting, LLC
859-586-4591
www.intra-spechomeinspections.com

Originally Posted By: tbramlett
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Thanks for the feedback everyone. You pretty much confirmed what I thought.


Originally Posted By: rbracklow
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Gentlemen,


In California, it is now a code requirement for all NEW Construction to have a vapor barrier either under the concrete if a slab, or above and on the ground if the property has a crawl space, or basement.

Ron