Maryland

As with Virginia, vented crawl spaces are considered the default with the Maryland building code. However, it’s possible to have a non-vented crawl space as long as you meet 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, so you can use almost any type.

However, unlike Virginia, Maryland code doesn’t require a termite gap. Again, “under-floor spaces” of all kinds have the following requirements:  

• Access openings through the floor or wall 
• Flood resistance in hazard areas

There’s very little information available here, largely because the IRC only sets minimum standards. That means the Maryland code only covers the bare minimum, so most crawl space experts have their own “best practices.” Talk to a crawl space expert to discover the right answer for your needs.