I'm renovating a Virginia home from the mid-1800's. The house is balloon frame construction, sitting on top of maybe four layers of brick, sitting directly on top of the dirt.
In the past, the crawlspace was not sealed and there was a lot of air movement under the house due to gaps in the foundation, which I have closed off with bricks and mortar. Half of crawlspace is inaccessible (no room to move under the floor joists), and the other half has a shallow access trench for the plumbing.
Presently, I have managed to poly and seal the half of the house with the access trench. My question is what to do about the other half of the house? There is no way to access it. There is a dirt floor, and no ventilation at all. By sealing up the accessible area, I have cut off all ventilation to the inaccessible area.
This house has never had air conditioning or insulation, but it does now. By installing these two things, I have significantly changed the environment of the house. I cannot assume the crawlspace will behave as it did over the past 100 years, during which it stayed dry and free of mold. Should I vent the dirt portion of the crawlspace by cutting vents into the foundation, or do I leave the dirt portion closed up?
Physical access to the dirt portion is not an option either way.