It's obvious looking at the old timber balanced on the interior walls at Chapman Mill that they have served the mill well. However to make the mill safe for visitors today new steel beams cross the interior walls to hold them up. If I had been around since the mid 1700's I'd need more than a steel beam to keep me upright.
Chapman's Mill is located in Prince William County off of Route 66 at the Haymarket exit. The mill grounds are open on the weekends from 9 AM to 5 PM.