Hi Laura,

I conduct any number of fire door inspections and certifications in a month, and the bottom clearance issue comes up a lot. First and foremost, I try to determine how they got where they are, i.e., uneven floor condition, over aggressive undercutting in the field etc. then I go about educating the owner on some simple solutions, like adding a threshold to help close the gap but a threshold isn’t always welcome. When this is the case then I discuss the bottom of door excessive clearance solutions on the market. They are all classified by their testing as “Fire Door Accessories” and their listings specifically spell out the use for correcting excessive clearance issues and the maximum oversized clearance they can remediate. The name brands I provide links to are National Guard Products, Pemko, Crown Fire Door Products, Zero International, and Active Fire Door Products.