2 Comments

1. 
   tamfflcommissioner | Dec 26, 2011 09:49am | #1

   Missing thermal
   Missing thermal boundary
   Missing air barrier
   Asbestos plumbing
   Knob and tube wiring
   Clay floor serving as a resevoir to foundation
   No capillary break

2. 
   Ted Clifton | Dec 28, 2011 11:22pm | #2

   How not to close a crawl space!
   Unfortunately, this picture could easily have been taken of the crawl-space of a house I happen to own. It was built in 1871, and is on the National Historical Register. The home worked well for over 100 years, because the crawl-space was left completely open. There were two wood-stoves and a masonry fireplace in the house, and a very leaky envelope, especially the wood plank floor. Wind would blow in under the floor, be warmed by the heat radiating through the floor, and pass through the crawl space much dryer than when it arrived, due to the fact that warm air with the same moisture content will have a lower relative humidity.

   At some point about thirty or forty years ago, the owners decided to close in the crawl space with mortar and rock, to make it appear that the house had a rock foundation, rather than wood piers. The mortar and rock not only sealed the crawl space, it also provided a cold surface on which to condense moisture. The leaky floors allowed moisture to enter the crawl space from above, and the moist soils and high water table allowed moisture to enter from below. That moisture condensing on the rock "foundation" was in direct contact with the wood rim-joist and siding. As areas of the rim and siding rotted away, the owners then decided to add more rock, following the rot up into the walls. More rock caused more rot, and now what was once considered a National Treasure will need to be destroyed, as the entire floor and the bottom several feet of the walls are rotten.

   Yes, there are many other problems with this picture, including the lack of a vapor-barrier on the ground, but the big culprit is closing off the foundation to the outside, without providing for the elimination of moisture within. I am a big fan of closed crawl space designs when they are done right, but it is usually very difficult to get it right on an existing home. If a vented crawl space is working well, I would usually advise leaving it alone!