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.
Measure the bottom of the doorway with a tape measure and buy an aluminum threshold to fit; most entry doors are about 36 inches wide. Match height of the new threshold to the old; make sure the new threshold is no higher off the floor to avoid door closing problems.