Automatic Drop Down Seals for Doors

The automatic door bottom is a clever bit of engineering that prevents under-door drafts, without installing a skirt that drags across your floor. Also called an automatic drop seal, it consists of an aluminum extrusion mounted in a dado cut into the bottom of the door. A little brass plunger protrudes from one end on the hinge side. As you close the door, the plunger is forced inside the assembly, where it triggers the spring-loaded seal to drop to the threshold, sealing the gap. Opening the door causes the seal to retract. Automatic door bottoms are useful not only for sealing drafts, but al