I have a south Louisiana home built in the 1950's with a vented crawl space. In the 70's, a den was added with a slab on grade foundation. In this addition, the back porch was converted into a landing with steps down to the floor of the den. From the crawl space, this former porch is perceived as a 7' x 14' "room" with brick walls, dirt floor and what appears to be a concrete ceiling with no exposed wood members. There is a single pier in the center. What used to be exterior vents have been sealed off with masonry. However, there are 2 interior vents/access holes that allow viewing (and squeezing) into this cavity from the larger crawl space. Due to it's location, there is zero chance of water intrusion from the outside into this area and no evidence of ground water, no efflorescence, etc. No plumbing or electrical passes through it.
I'm planning an encapsulation of my crawl space and am trying to figure out how to treat this area. Quite simply, I would like to exclude it from the conditioned space in order to minimize the labor AND to minimize the load on the dehumidifier. My thought is to seal off one of the access holes and install a sealed door on the other for inspection purposes. This would effectively create a tiny, sealed off but unconditioned "room" with a dirt floor under our house.
Does this sound like a reasonable approach? Could I potentially be causing a future problem in doing this? I plan on doing a radon test before proceeding.
