Most modern thresholds have adjustment screws along the top that raise or lower the sill cap to meet the door sweep. Turning them evenly usually eliminates a floor draft for free. If the threshold is maxed out, replace the sweep for fifteen to forty dollars.
This is the single cheapest meaningful repair in a house and almost nobody knows it exists. If cold air is coming in under your exterior door, the fix is very likely four screws and ten minutes.
Here is how it works.
How an adjustable threshold works
Look at the top surface of your threshold, the metal or composite piece the door closes down onto. On most thresholds manufactured in the last thirty years you will see a row of screws, typically three to five, set into the cap. Those are not fasteners holding the threshold down. They are adjusters. Turning them raises or lowers the cap independently of the threshold base, so the cap can be brought up to meet the door sweep. Over years, the door settles slightly on its hinges and the sweep compresses, and the gap opens. Raising the cap closes it again. Turn each screw a quarter turn at a time, working evenly across all of them, and test the door after each pass. Stop when the door closes with light resistance and the sweep contacts along its full length. Going higher makes the door drag and wears the sweep out quickly.
Sweeps and bottoms
| Type | How it attaches | Cost | Best for |
|---|---|---|---|
| Surface mounted sweep | Screws to the door face | $10 to $25 | Quick retrofit, visible |
| Kerf-in door bottom | Slides into a slot in the door edge | $15 to $40 | Most modern prehung doors |
| U-shaped slip-on bottom | Slides over the bottom edge | $15 to $35 | Doors with no kerf |
| Automatic door bottom | Drops when the door closes | $45 to $120 | Interior doors, sound, accessible thresholds |
| Door shoe with vinyl insert | Mechanically fastened to the bottom | $25 to $60 | Heavy use exterior doors |
| Threshold replacement | Full unit, new sill cap and base | $120 to $350 | Worn, cracked or rotted threshold |
When the threshold itself has to go
- The adjusters are seized, rounded out, or turn without raising the cap.
- The cap is cracked, split or has worn through.
- The substrate under the threshold is soft, which you can feel as movement when you step on it.
- Water is visibly getting past the threshold into the floor below.
- The threshold is wood and the exposed edge has rotted.
- The threshold height does not meet accessibility requirements at an entrance that needs to.
- You are replacing the door anyway, in which case a new prehung unit comes with a new threshold.
The wider point
Thresholds and sweeps are consumables. They are designed to wear and to be adjusted and replaced, the same way brake pads are, and they cost under fifty dollars. A remarkable number of people live with a cold draft across the floor for years, or replace an entire door, when the actual issue is a sweep that has compressed flat after ten thousand closings. Before you get quotes on a new door, spend ten minutes on the threshold adjusters and another twenty on a new sweep. If the draft stops, you have saved a few thousand dollars. If it does not, you now know the problem is somewhere else, which is useful information to bring to the estimate.
Ranges reflect typical Capital Region projects and are for planning only. Every Sundog quote is written, itemized, and free.
Frequently asked questions
How do I adjust my door threshold?
Find the row of screws set into the top of the threshold, usually three to five of them. Turn each a quarter turn clockwise at a time, working evenly across all of them, and test the door after each pass. Stop when the door closes with light resistance and the sweep contacts along its full length.
How do I know if my door sweep needs replacing?
Close the door and look at the sweep from outside at ground level. If the vinyl or rubber is compressed flat, cracked, torn, or no longer springs back when you press it, it is done. If the threshold is already adjusted to its maximum and there is still a gap, the sweep is the remaining variable.
How much does a door sweep cost?
Fifteen to forty dollars for most types, and installation is straightforward on a kerf-in or slip-on bottom. A door shoe or an automatic door bottom runs more, twenty-five to a hundred and twenty. A full threshold replacement runs $120 to $350 installed.
Why is my door dragging on the threshold?
Usually the threshold has been adjusted too high, or the door has swollen with humidity, or the hinges have loosened and the door has dropped. Lower the threshold adjusters a quarter turn at a time first, since that is free and reversible. If it still drags, check the hinge screws and consider a longer screw in the top hinge.
Can I replace a threshold myself?
On a wood-framed opening, it is achievable with basic tools, though the old threshold is usually fastened and sealed thoroughly and removal is the hard part. Where it stops being a homeowner job is when the substrate underneath is rotted, because at that point you are into framing repair and a proper sill pan.
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