A worn or damaged door threshold lets in drafts, rain, and insects. Replacing it restores the weathertight seal at the bottom of your exterior door and can noticeably improve your energy bill.
STEP 1: Remove the Old Threshold
Open the door fully. Most thresholds are held down by screws driven through the top into the subfloor. Remove all screws and pry the threshold up carefully with a flat pry bar. If caulk is bonding it to the door frame, score the edges with a utility knife first.
STEP 2: Clean and Inspect the Subfloor
With that foundation in place, scrape away old caulk, debris, and any rotted wood from the area beneath the threshold. If the subfloor is soft or damaged, patch it with exterior wood filler or replace the damaged section before installing the new threshold.
STEP 3: Measure and Cut the New Threshold
The next step builds on everything so far. measure the width of the door opening precisely. Most adjustable thresholds are sold in standard sizes and can be cut to length with a hacksaw. Cut slowly and file the cut end smooth to prevent sharp edges.
STEP 4: Install the New Threshold
Taking this a step further, dry-fit the threshold in the opening and check that the door clears it when closing. Apply a bead of exterior silicone caulk to the subfloor, set the threshold in place, and drive the provided screws through the pre-drilled holes. Do not overtighten — snug is enough.
STEP 5: Adjust the Height for a Proper Seal
Finally, to make everything sustainable, most modern thresholds have adjustable screws along the top that raise or lower the vinyl seal. Close the door and adjust these screws until the bottom of the door compresses the vinyl strip evenly across the full width — tight enough to block air but loose enough that the door closes without excessive force.
PRO TIPS
Q: How do I know when to replace a door threshold?
A: Buy an adjustable threshold — the screws on top let you raise or lower the seal to compensate for uneven floors or a door that has settled over time. A fixed-height threshold either seals too tight or leaves gaps with no way to adjust.
Q: What is an adjustable door threshold?
A: Apply a continuous bead of exterior silicone caulk under the entire threshold before screwing it down. This creates a waterproof barrier that prevents rain from seeping under the threshold and into your subfloor.
Q: How do I seal the gap under my front door?
A: If your door still lets in a draft after replacing the threshold, the problem may be the door sweep or weatherstripping on the sides and top of the door — not the threshold. Check all four sides for gaps and address each one.
SUPPLIES NEEDED
Adjustable door threshold
Hacksaw for cutting to length
Drill and screwdriver bits
Exterior silicone caulk
Pry bar
Utility knife
Tape measure
File
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