I’m renovating a 120 year old industrial loft in Chicago, with the intent to get rid of the 1990s finishes I currently have to bring out the old industrial look. This is a structural concrete building with huge concrete columns running throughout the unit. I want to take up my wood floor and polish the concrete subfloor to bring back that loft look. My GC has discovered another wood floor, and subfloor under my existing floor. We are estimating a 6” different between where the concrete floor is and the height of the front door, I’m less concerned about the same height difference with my patio doors. I need a solution so that people don’t trip entering and leaving my unit, and can’t find a good one. I have a designer working on this, but was wondering if anybody has a good fix, that will keep the unit safe, and maintain the look of an industrial loft.