Technical Papers

Moldy Crawl Space in Round Hill Va

Thursday, September 11th, 2014 by John LeVan

Round Hill Va. Crawl Space is Reborn

 

We had the opportunity to help a customer who owns a lovely home in Round Hill Virginia.  This home owner had tried to maintain her crawl space and make repairs to it over the years, but had hired construction people who did the wrong work to fix a crawl space.

 

The home actually has three separate areas of crawl space, each of which exhibited excessive moisture. Condensation dripped from pipes and framing materials. Mold growth and a plethora of wildlife that had taken up residence beneath the owners living space.  We affectionately referred to the property as “The Snake House” as we found the skeletonized remains of more than 20 snakes entangled in the mold infested insulation.

The first crawl space exhibited very tight access (less than 18 inches of clearance).  A previous contractor had tried to fix the cold floors in this space by using open cell spray foam on the underside of the sub floor.  This is not an effective solution for several reasons.  1) Open cell spray foam should not be used in underground environments or near open earth.  Why?  Because it is open cell, not a vapor barrier and allows moisture to penetrate the foam and then keeps the substrate (in this case plywood) wet. 2) They did not isolate the house from the earth.  The ground had some 6 mil plastic spread out on top of the soil, but it provided no protection from vapor intrusion . 3) The contractor did not move the envelope to the walls and floor of the crawl space.  In fact they left the crawl space vents open to the environment allowing hot humid air to enter the space and further the condensation issue on the framing, pipes and ductwork.  We improved the environment here by Installing Terrablock™ Insulation on the floor, followed by Cleanspace ™ liner to prevent vapor intrusion and finally closed cell insulation in the walls to seal the crawl space from the outdoor environment.

The second crawl space was under the original house, a 3 foot high affair with damp walls and insulation that was hanging from the rafters due to a moisture content that was in the high 80% range.  This wet damp insulation was a source of moisture that was feeding extensive mold growth.  The rooms above this area had a musty smell as a result.  We removed the damp insulation, cleaned the mold with industrial strength hydrogen peroxide (Remedia 1™) and then HEPA vacuumed the spores after it dried.  All insulation was removed from the duct work and it was then sealed and insulated with low pressure spray foam.  We treated the floors with Terrablock ™ and then insulated the walls with Silverglo ™ foam board.  Lastly, as this crawlspace was in the center of the house, we installed a Sanidry dehumidifier to bring the humidity level in the crawl space down to a number that will not support rapid mold growth.

The third space contained the HVAC unit.  We treated this much like crawl space number 2, and then had Atlantic Duct Cleaning  www.atlanticductcleaning.com clean the HVAC system.  See the photos of the remarkable difference in our case study section. 

This was a large and challenging project that included Mold Remediation, Spray Foam, crawl space Encapsulation, Ductwork Cleaning, Sealing and Insulation.  We worked collaboratively with the Industrial Hygiene firm Inlogix (www.inlogix.com) to iron out questions we had related to the execution of their protocol for treatment.  By following the detailed instructions in the protocol, and following the guidelines established in the IICRC S520 standard for mold remediation we were successful. 

What makes us most proud is that the home owner indicates that it smells better in her living space, there is an absence of critters in the crawl space and an environment that is now under control.

If you have a musty crawl space let Comfenergy Help you.  We can help you engage an Industrial Hygiene firm if the project is complex like this one was.

About the author
John LeVan is a Mechanical Engineer trained at Columbia University School of Engineering and Applied Science. John also has an advance degree in Operations Management from Cornell University.
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