Midrexâs primary business is direct reduction ironmaking. We build DRI plants that work day in and day out, year after. year to provide value for our clients so that they can make. the most of their investment and maximize their profits for. years to come. The MIDREXÂ® Process 2. The MIDREXÂ® Process.
Quick Answer. The maximum interior height of an entry door threshold is 1/2 inch, and up to 3/4 inch on exterior siding doors where it is essential to keep water out, as stated by the United States Access Board. These height limits improve wheelchair access to buildings.
Door Heights. The height of common doors is 6 feet 8 inches. The standard height of the rough opening for a door is the door height plus 2 5/8 inches. The additional room allows for a 3/4-inch top jamb, a shim space above the door jamb and the thickness of underlayment and finish flooring.