Virginia’s building code accepts vented crawl spaces as the default, only allowing for non-vented crawl spaces in certain situations. These situations are a little more nebulous and less well-defined than the exceptions in North Carolina’s code. You can have a non-vented crawl space as long as the space meets the following requirements:
- Certain minimum coverage with a vapor barrier
- A method of mechanical crawl space ventilation that meets a certain rate of ventilation; the residential code doesn’t mandate the type of ventilation
- A termite inspection gap of 1-2 inches
All “under-floor spaces” also have the following requirements:
- Access openings through the floor or wall
- Flood resistance in hazard areas
The Virginia building code is notably lacking in information for both vented and unvented crawl spaces. A crawl space expert will be able to help you determine the right choices for anything that’s not covered.