Efficient method for finding a sealed room on a 2D gridspace?

I'm currently making a game that uses a 2D gridspace for objects, and I'm trying to figure out how I would find a space that has been sealed by floors and airlocks/walls. The way I define positions is like this: Workspace>TileObjects>Object>Position>0,0

Position is an objectvalue of the actual position object, which is a stringvalue that also contains the position. This is so I can easily find an object at a position by using :FindFirstChild().