You hear that scrape every time you open the back door. Here's how to figure out whether it's the threshold, the sweep, the door itself, or something worse - and what each fix actually costs.
Four causes account for 95% of back-door scrape complaints in PSL: a swollen wooden door from Florida humidity, a worn-flat sweep, a heaved or sagged threshold, or hinge sag dropping the door 1/4 inch.
Fastest test - close the door and look for the scrape mark on the threshold and sweep. Fresh scrape on the metal threshold = door dropping or sweep gone. Scrape on the door bottom = threshold rising. Even contact = weatherstrip needs swap, not a structural problem.
Doctor Lockout repairs and replaces thresholds, sweeps, and hinges on commercial and residential back doors across Port St. Lucie, Stuart, Fort Pierce, and the Treasure Coast. Same-day service in most cases. Call (772) 284-5142.
Threshold drag has two ways of starting: the threshold rises into the door, or the door drops onto the threshold. The fix depends entirely on which one.
30-second diagnostic:
That tells you which of the next four sections to dig into.
Most common cause on residential back doors. Wood doors sag from gravity over time, especially after 10+ Florida summers when the door has been opened and closed 30,000 times and the hinge screws have walked loose in their pilot holes.
To confirm: stand outside, open the door 30 degrees, then look at the gap between the door's top edge and the head jamb. If the gap is wider on the latch side than the hinge side, the door has rotated downward.
Three fixes by severity:
For commercial back doors with continuous hinges or heavy ball-bearing hinges, see our commercial door hinge service.
| Drag Cause | Diagnostic Tell | DIY Fix? | Cost If Locksmith |
|---|---|---|---|
| Hinge sag (loose top screws) | Top of door drops 1/8"+ | Yes - longer screws, 15 min | $60-$120 |
| Threshold has shifted | Visible gap or rocking | Sometimes | $140-$320 |
| Door has warped from heat / moisture | Door no longer flat | No | $280-$640 + new door |
| Frame has dropped / settled | Whole frame tilted | No - structural | $240-$520 |
The sweep is the flexible strip (rubber, vinyl, or brush) attached to the bottom edge of the door that seals against the threshold. After 3-5 Florida summers, the rubber gets hard, the vinyl tears, or the brush gets matted flat. Then it either drags or it folds under and gets ripped off entirely.
You'll see this as:
Replacements we keep on the truck:
Sweep swap is 15-20 minutes including cleanup. We'll usually offer the option to also re-shim the threshold while we're at floor level - $35-$50 add-on that prevents the next problem.
Real locksmith, real ETA, honest price quoted before any tools come out. 15-30 minute arrival across the Treasure Coast.
Call (772) 284-5142Florida concrete-slab buildings move. The slab heaves up at expansion joints, settles unevenly at corners, or shifts after a hurricane. When the threshold is bolted to a moving slab, it moves with the slab - and your door bottom doesn't.
Three threshold problems:
Standard threshold replacement uses Pemko 277A (aluminum with thermal break and vinyl seal) for most commercial and residential entries. Installed cost runs $245-$385 for a single door, more for double doors with astragal.
See our threshold replacement service.
Wood doors swell in PSL humidity, especially during the late-July-through-September stretch when relative humidity stays above 80% for weeks. A door that fit perfectly in February can drag the threshold by August.
Two scenarios:
For composite, fiberglass, and metal doors, swelling isn't the cause - look at one of the other three reasons instead.
Real 2026 pricing from our trucks:
Quotes are given in writing on-site before any work, and we tell you when a $35 screw will fix what a competitor will quote as a $300 threshold.
DIY-friendly:
Call Doctor Lockout when:
Three things to know about back-door drag in our climate:
Saltwater corrodes thresholds within sight of the Indian River Lagoon and the Atlantic. Hutchinson Island, Jensen Beach waterfront, Stuart Causeway, Rio. Aluminum thresholds pit and split within 8-12 years. Stainless or bronze costs more but lasts 2-3x as long.
Hurricane shutters bolted to the doorframe can shift the frame when installed or removed under pressure. We see this every fall after storm season - shutter brackets get over-tightened, the frame racks 1/8 inch, the door starts scraping. Easy fix: shutter-bracket re-torque plus threshold re-shim.
Termites in older PSL homes can eat the wood framing under the threshold without you ever knowing. If the door drags AND the threshold feels spongy when you press on it, get a pest inspection before you replace the threshold. Otherwise you're putting new hardware on rotten wood.
Humidity. Wood doors and frames absorb moisture during PSL summer (June-September), expanding the door 1/16 to 1/8 inch. Composite and metal doors don't swell, but the frame around them can shift slightly from concrete-slab expansion. If the drag clears up by November, you can live with it or seal the door faces with marine polyurethane to slow moisture intake.
For wood doors, yes - planing the bottom is faster and cheaper. For composite or fiberglass doors, no - the door has a sealed bottom rail and planing it voids the warranty and exposes the foam core. For metal doors, planing is impossible. In those cases, threshold or sweep replacement is the right answer.
15-25 years for the aluminum body. The vinyl seal insert wears out faster, typically 5-8 years, and is a $35 parts replacement we can do without pulling the threshold. Coastal exposure (Hutchinson Island, barrier islands) cuts these times by about 30%.
Usually yes if the drag is severe enough to prevent the door from latching, or if there's visible damage to the threshold or door bottom. A mild scrape that doesn't affect operation is often noted but not flagged as a defect. For a pre-sale inspection in PSL, fix anything that scrapes audibly - it's cheap insurance.
Yes, more often than people realize. Shutter brackets bolted into the door frame can torque the frame 1/16 to 1/8 inch out of square when tightened, and that's enough to put the door bottom into the threshold. After storm season, if you reinstall shutters and the door starts dragging, check the bracket torque first before assuming the threshold moved.
Yes, this is daily work for us. Restaurant back doors, retail receiving doors, warehouse pedestrian doors - we carry Pemko 277A, 252A, and 174A on the truck plus the commercial-grade screws and concrete anchors. Most jobs finish in 60-90 minutes on-site.
Doctor Lockout runs 24/7 across the Treasure Coast. Real person on the phone in under 2 rings, locksmith on-site in 15-30 minutes, honest quote before any work starts.
Call (772) 284-5142Doctor Lockout serves Port St. Lucie and the entire Treasure Coast 24 hours a day, including these neighborhoods and surrounding cities:
Last updated: 2026-05-18
