Replies

1. 
   notatexan | May 04, 2009 07:47pm | #1

   I am no expert but I am renovating a small house right now and following the advice from BulidingScience.com, Research reports, Conditioned Crawl spaces.  Doesn't address rain in the crawl space (I have that problem also) but shows how to permanently fix the moisture in the crawl space problem. 

   Be sure to check with the Building Inspector.  My BI was not aware of the new research showing the problems with vented crawl spaces.  He said he would do some reading before my fraiming inspection.

   Many threads in Breaktime on the subject.

   Jim

2. 
   twalkman | May 04, 2009 09:31pm | #2

   moisture will come out of the soil. If you're going to close the vents, you also need to vapor barrier and seal the seams.

1. 
   greenbhindtheears | May 05, 2009 07:15am | #3

   I have a vapor barrier and poured a "rat" slab in the crawlspace. I am mostly concerned about the potential for existing growth. Any thoughts?

1. 
   talkingdog | May 05, 2009 10:19am | #4

   Airflow kills mold. My book from Building Science has various schemes for mechanically ventilating the sealed crawlspace using inline fans, etc. I think you really need mechanical ventilation. Around here the savvy builders use a multiport fan with long intake ducts set to the corners of the space. My approach is to just make it a separate room in the HVAC ductwork, and return the air via HRV.Another question is what is the humidity level in the crawlspace? If the concrete is new, the humidity may just be the temporary result of the gradual release of the many gallons of water in the slab.

1. 
   greenbhindtheears | May 05, 2009 05:44pm | #6

   The slab is 6 months or so. The moisture is from having the construction process happen over the winter and water just absorbing into the wood structure of the floor. I should also mention that now there is an inch and a half of gypcrete on top of the sub floor with hydronic heat in it. If there is any moisture in the crawlspace, or more specifically between the insulation and the sub floor I am worried that the warmth could grow wonderful things. I have temporarily taken all of the under floor insulation down and have some pretty good air movers down there and things seem to be dry. I don't think that more moisture can get there unless a leak develops:( or something. Thanks for the insights.

2. 
   twalkman | May 05, 2009 03:56pm | #5

   Sounds like you have it in good shape. You can get products at HD to kill any existing mold via spray or fog. For the mildew smell, you probably just need to circulate some air, or get a dehumidifier.

1. 
   greenbhindtheears | May 05, 2009 05:45pm | #7

   Do you know what kind of fog or where to get something like that?