Crawl Spaces

I received a call from a previous inspection client recently.  When I inspected her house the crawl space was dry and there was plastic ground cover with no signs of water.  During the recent rain her crawl space became wet with standing water.  She had a contractor look at it and was told the plastic should have been run 1/2 way up the block and sealed to the block.  I did see this once on “Mike Holmes” but I have never seen it done around here.  Is this a new requirement?  Thanks

     You do not say when the home (or crawl) was built and if this is a vented crawl.  That makes a difference.  Starting with the 2006 IRC (the 2008 Ky residential code incorporated a version of the standard), unvented crawl spaces were addressed.  Previously, the standards just required venting all crawl spaces. 

    It sounds like your client’s contractor is talking about the standards for unvented crawl spaces.  In an unvented crawl space, ventilation openings under the prior rule were not required IF dirt is covered with “a continuous vapor retarder” (typically 6 mil plastic) that overlaps by 6 inches and is sealed or taped at the seams.  The standard also provides that the vapor retarder “shall extend at least 6 inches up the stem wall and shall be attached and sealed to the stem wall.”  The standard also requires either conditioning the space or providing for continuous mechanical exhaust.
    However, “1/2 way up the block” is not part of any standard, unless (of course), the crawl stem wall is 12 inches high (which would make the 6 inch requirement = 1/2 the stem wall).
    That standard is at R408.3, if you want to look it up for your own reference, but (obviously) reporting code compliance per se is prohibited for Kentucky home inspectors.  It’s one guide and one source of standards for home inspectors, as in the part of your questions about a “new requirement.”
    Otherwise, the prior standard (R408.1) applied, which looked for covered vents providing at least 1 sq ft of ventilation for every 150 sq ft of under-floor space, and a vent within 3 feet of each corner.  That standard was coupled with a rule for “below-grade moisture barriers” (R406.3.2) that applied to the exterior foundation walls (but does not apply to your problem).  Notice that neither older standard (they are still in effect) mandated plastic vapor barriers over dirt floors in crawl spaces, until the unvented crawl rule was added a couple of years ago.
Homes built before those standards became  enforceable were “grandfathered”  each time new rules were adopted, no matter how the crawl space moisture was managed or whatever later codes required.
Putting aside the vapor barrier standards, our basic concern is performance.  If the crawl was performing its intended function (and safe) at the time of inspection, as far as you could see, then it seems unlikely there was a “significant deficiency”  that our statute requires inspectors to report.  Obviously, though, if there was standing water in the crawl space, you have to think something wasn’t right.  The only places water is intended to enter a home is bathrooms and kitchens.  That does not mean any inspector could see an underground spring in a drought, for example.  It does mean that a 6 mil plastic vapor barrier is no match for an underground spring in the crawl, though.     
Call Now Button