Worn or Leaking Door Threshold: Adjust It, Reseal It or Replace It?
What this comes down to
- A leaking threshold is often sound. The fault is usually the door sweep, the adjustable cap or the caulk under it.
- Most adjustable thresholds rise with a few screw turns, until a playing card drags as it slides out.
- A threshold that flexes underfoot usually sits on a rotted sill. A new strip alone will not hold.
- At the main exit door, code keeps the inside floor within 1.5 inches of the top of the threshold.
- Accessibility guidance caps a new threshold at half an inch high, beveled above a quarter inch.
- Replacing a threshold over a sound subfloor is a short job. Rot underneath makes it a frame repair.
A door threshold takes more abuse than almost any other part of a house. Every footstep, storm and freeze lands on a strip of aluminum and wood a few inches wide. It wears, and in time it lets air or water through.
This guide covers how to tell a threshold that needs adjusting from one that needs replacing. It also covers the sill beneath it and the height limits. Last comes what cannot be judged until the old strip is out.
Why does a door threshold leak?
Usually because the seal above it has failed, not the threshold itself. The sweep on the door bottom and the cap on the threshold have to meet. When either one wears down, air and water pass between them.
The second route is underneath. A threshold is bedded on a bead of sealant across the subfloor. When that bead cracks, water running off the door slips under the strip. Wet floor past the inside edge is the sign.
Can a worn threshold just be adjusted?
Often, yes. Most exterior door thresholds made in recent decades carry an adjustable cap. A row of screws along its top raises or lowers the cap to meet the sweep on the bottom of the door.
Pease, an Ohio door maker, gives a simple test in its threshold installation steps. Slide one playing card under the closed door. It should pull out with a little tension, neither falling free nor sticking.
If the card drops through, the cap goes up a turn at a time until it drags. If the card will not move, the cap comes down. A cap already at the top of its travel means the sweep is the part that has worn.
Sweeps are the cheapest piece of the assembly. Most slide into a groove in the bottom of the door, or screw to its face. A torn or flattened sweep is replaced, and the cap is then reset to meet it.
How do you tell a worn threshold from a rotted sill?
By standing on it and probing what is under it. A worn threshold is scuffed, loose or low in the middle. A rotted sill makes the whole strip flex underfoot, and often darkens the floor beside it.
Push an awl into any exposed wood at the threshold ends, and into the bottom of each jamb. Sound wood stops the point. Wood that lets it sink in is rot, and rot has usually spread further than it shows.
That changes the job. A new threshold screwed down over a soft sill works loose within a season. The guide to spotting a rotted frame covers the signs. Many of them start at the threshold.
How high can a door threshold be?
Low enough that nobody trips on it. For the main exit door of a house, the International Residential Code sets the limit. The inside floor may sit no more than 1.5 inches below the top of the threshold.
The same code section lets the outside landing sit up to 7.75 inches lower. That applies where the door does not swing over it. It is why a front door can step down onto a stoop while the floor inside stays level.
The federal Access Board sets a tighter figure for public buildings under the ADA standards. Its guide sets threshold height limits at half an inch for new work, beveled above a quarter inch.
An existing threshold may reach three quarters of an inch if both edges are beveled. None of this binds a private house. It does describe a threshold that will not catch a walker, a wheelchair or a slipper.
Will a new threshold stop a draft?
Only if the draft is coming under the door. A Virginia Cooperative Extension fact sheet puts doors at 11 percent of a typical home's air leaks. It takes that figure from the Energy Department.
The same fact sheet gives a quick check for gaps. Close the door on a dollar bill. If the bill slides out easily, the weatherstripping at that spot needs repair or replacing.
It also warns that a gasket threshold, with a rubber insert, wears quickly in heavy traffic. A door shoe fixed to the door bottom suits any threshold that is not worn in the middle.
What does replacing a threshold involve?
More than unscrewing a strip. The old threshold is usually cut in half and levered out. Pease notes that three or four screws often run through the jambs into its ends.
The space is cleaned down to bare subfloor and probed for rot. The new threshold goes down on a heavy bead of sealant along its underside. It slides in from inside the house, outer edge first.
Newer flooring is the usual complication. If the floor has been built up since the door went in, the threshold cannot slide in from inside. The foot of each jamb is then trimmed to let it pass.
What does threshold work cost?
Most threshold work falls between the $99 minimum call and a couple of hours at $65. A rotted sill underneath moves the job onto the frame repair lines. The figures below are starting prices, not quotes.
| The work | Starting price | Wider market | What moves it |
|---|---|---|---|
| Minimum service call | $99 minimum | $120 to $200 typical | Whether a sweep or cap is replaced on the day |
| Hourly rate after that | $65 per hour | $60 to $125 / hr in Illinois | Whether the jambs must be trimmed for newer flooring |
| Rotted door frame repair, localized | From $249 | $300 to $800 | How far the rot runs from the sill into the subfloor |
| Significant rot or partial jamb replacement | From $395 | $500 to $1,000 | Whether both jamb feet and the rim joist are affected |
| Exterior door replacement, installed | From $695 | $800 to $2,500 | Door type, and whether a sill pan is added |
The frame lines are explained in the guide to frame repair costs, including why rot comes back. Where the whole door goes, the replacement cost guide covers what moves that price.
What cannot be determined from the doorway?
Whether the subfloor under the threshold is sound. The strip covers it completely. A probe at the ends gives a hint. Only lifting the threshold, or looking up from below, settles it.
Whether the opening has a sill pan cannot be seen either. Many older doors went in without one. It only shows once the threshold is out, and adding one means taking the door unit out.
And whether a matching threshold is still made for the door. Some makers use their own profile, and the cap and sweep have to fit it. An unlabeled door may need a universal strip and a new sweep together.
Door threshold questions
How do I know if my door threshold needs replacing?
Replace it when it is cracked, loose, worn through in the middle or flexing underfoot. A threshold that only leaks usually needs its cap raised or a new sweep. Flexing points to a soft sill below, which is repaired before any new threshold goes down.
How does Perfect Work decide between adjusting and replacing a threshold?
Perfect Work Remodeling & Repairs tests the seal with a card, then checks the cap and sweep. The threshold ends and jamb feet are probed for rot. A sound threshold gets adjusted. A worn one is replaced, and any rot below is quoted separately.
Can I replace a door threshold without replacing the door?
Yes, in most cases. The old strip is cut out and the subfloor cleaned and checked. A new threshold is then set in sealant while the door stays hung. The exception is rot in the jambs or subfloor, which makes it a frame repair.
Why is there water under my door threshold?
Usually the sealant bead under the threshold has cracked, or the opening has no sill pan. Water running off the door then passes beneath the strip. Water between the door and the cap is different: the sweep or cap is at fault.
What does a threshold repair visit from Perfect Work include?
A visit from Perfect Work Remodeling & Repairs covers the sweep, cap, bedding and nearby wood. Adjustments are made on the day where they fix the problem. Rot or a missing sill pan is written up and priced before any further work starts.
How high should an exterior door threshold be?
At the main exit door, the inside floor may sit at most 1.5 inches below the threshold top. Accessibility guidance for public buildings uses half an inch, beveled above a quarter inch. A low threshold is the safer choice at a busy door.
Sealing the bottom of the door
Most threshold trouble is a worn sweep, a cap set too low or a cracked bead of sealant. Each is a short fix. The exception is a threshold that flexes, which nearly always means a rotted sill.
Perfect Work Remodeling & Repairs starts each threshold visit with a card test and a probe. Small fixes are billed as hourly handyman work. Anything larger falls under door repair and replacement.
Call Perfect Work at 630-297-7888 · Book a door check