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How to Install a Floor Exterior Door Transition

Exterior door thresholds come in a variety of styles. Each one, however, serves the same purposes. They ease the transition from the outside to the inside, as well as build up the bottom of the door opening to prevent drafts and rain water leaking in. Exterior threshold installation is a straightforward project that does not require removal of the door or door jambs. Plan on spending about three hours with this project.

Things You'll Need

  • Hammer
  • Chisel
  • Reciprocating saw
  • Tripolymer caulk
  • Caulk gun
  • Torpedo level
  • Wooden shims
  • Utility knife
  • 2-inch wood screws
  • Drill
  • Phillips driving bit
  • Polyurethane sealer
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Instructions

    • 1

      Hammer a chisel beneath the old door threshold and the door opening. Slide a reciprocating saw into the gap the chisel creates. Run the saw back and forth underneath the threshold to cut through the nails holding it in place.

    • 2

      Make two cuts through the old threshold, one near the right side and one near the left side. Slide the center portion out. Wiggle the two ends back and forth to loosen them and slide them out from underneath the side jambs.

    • 3

      Insert a tube of tripolymer caulk into a caulk gun. Run two or three beads of caulk over the subfloor, where the new threshold will rest. Slide the threshold underneath the side jambs. Lay a torpedo level across the threshold. Insert wooden shims underneath the threshold to lift any low areas up.

    • 4

      Score along the wooden shims that extend past the new threshold's edge with a utility knife. Bend the shims back and forth until they break off along the score line.

    • 5

      Secure the threshold in place with either 2-inch wood screws or fill the area beneath the threshold with polyurethane sealer and close the door. If you use the sealer, leave the door closed for at least three hours to help hold the threshold in place.