There are two major problems with subterranean space in the housing industry- concrete and dirt foundations in basements and vents in crawl spaces.
Concrete and dirt are both porous materials, and when basement and crawl space walls and floors are built out of these materials, moisture from around the foundation is able to constantly pass through. This is what makes basements the infamously damp, dreary, and moldy spaces.
Likewise, the vents in crawl spaces also let in enormous amounts of humidity in the summer. When warm air rises in a home, it exits through the upper levels. This creates a vacuum in the lower levels, which pulls air upwards from the crawl space. This in turn creates a vacuum in the crawl space, and air is pulled from the vents to replace it. So crawl space vents don’t ventilate air so much as they pull air in from the outside. This pulls humidity in the crawl space and home, causing rot, mold, and mildew in the space. Wet wood attracts termites, and rotting crawl spaces lead to sagging floors and possible structural damage, so the problems begin to stack on top of themselves pretty quickly. And in the winter, the same crawl space vents will allow cold air into the crawl space, which also saves on utility bills.

![[del.icio.us]](http://www.basementsystems.com/blog/wp-content/plugins/bookmarkify/delicious.png)
![[Digg]](http://www.basementsystems.com/blog/wp-content/plugins/bookmarkify/digg.png)
![[Reddit]](http://www.basementsystems.com/blog/wp-content/plugins/bookmarkify/reddit.png)
![[StumbleUpon]](http://www.basementsystems.com/blog/wp-content/plugins/bookmarkify/stumbleupon.png)
![[Technorati]](http://www.basementsystems.com/blog/wp-content/plugins/bookmarkify/technorati.png)