Replies

1. 
   Bob_Walker | Mar 07, 2001 01:55am | #1

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   Bag the vents and condition the crawls. If your code inspector hesitates, tell him I said a conditioned crawl is much better than venting.

1. 
   Steve_Zerby | Mar 08, 2001 03:07am | #2

   *John,This question cannot be addressed without knowing where you are and what your summer temp and humidity levels are, though odds are that Bob's advice is correct.Steve

1. 
   John_Martin | Mar 08, 2001 05:57am | #3

   *I'm in the Pacific Northwest. We have mild but wet winters (usually). This year has been very dry!

1. 
   Steve_Zerby | Mar 10, 2001 06:48pm | #4

   *John,It's not the winters that are the problem, it's the summers.In summer the humidity in the air is relatively high. When that humid air enters the crawlspace, if the crawlspace temperature is below the dewpoint, condensation will occur. Only in the most arrid of conditions is this not a problem. Barring any internal moisture sources such as groundwater problems or active plumbing leaks, closing off the vents helps more than opening them. The only time most vents will actually help dry the crawlspace is in the winter time.Steve

2. 
   John_Martin | Mar 10, 2001 06:48pm | #5

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   What is the correct way to calculate how to mechanically ventilate a crawlspace foundation. The building is part of a duplex and is impossible to get required amount of standard fndn. vents and cross ventilation.
   Our code requires 1/150 area for vents. How many CFM's or air changes per hour would be required?