Reader problem: The bottom sweep scrapes near one corner but barely touches the threshold at the other. A thicker or shorter replacement sweep is not automatically the answer. First distinguish an uneven contact pattern, an asymmetric door/threshold position, and an existing sweep mounting problem—without altering door hardware.
Start with a position map, not a guessed gap size
With the door in its ordinary safe closed position, note the side where the rub occurs: hinge end, latch end, or center. Take one wide photo showing the entire threshold and one angled photo showing both the bottom of the door and the threshold surface. Make a quick annotated diagram of the scrape line. If the scrape changes as the leaf moves, record where in the swing it starts, but never force a sticking door or hold a required exit open to run a test.
| Pattern | Observation to collect | Still unverified |
|---|---|---|
| One-end heavy scuff, opposite end almost untouched | Does the bottom edge look parallel to the sill when shut? Is one side visibly worn? | Whether hinges, frame, floor, threshold or sweep caused it |
| Rub appears only while the door swings | Identify the arc or position where contact begins and its side | Whether a specific profile height is wrong |
| Entire sweep drags evenly | Photograph the continuous wear line and existing mounting position | That trimming or a thinner replacement is permitted |
| Contact varies with temperature or moisture | Photograph/date the condition on separate days | Whether seasonal movement is the cause |
Distinguish the part being measured
There are three different objects: the sweep's flexible wiping edge, its retaining carrier, and the fixed threshold. Mark each one separately in photographs. A plastic blade can be curved from age while an aluminum carrier remains in position; conversely, a firmly held blade can rub because the threshold or door position changed. A loose offcut, if already available, may help identify a cross-section, but its height off the door is not installed clearance.
For a safe observational record, measure only an unloaded visible threshold step and the accessible sweep/carrier dimensions with a ruler held alongside, not underneath a loaded door. Record units and measurement points. Do not wedge a gauge under a rated/fire door, alter a closer, remove hinges, plane the leaf, or adjust a threshold based on this page. If you cannot clearly see a dimension, write UNKNOWN.
Three short cases a reader can tell apart
Case 1 — scrape at latch end: Your first question is whether the sweep is uniformly mounted and the door/threshold relation is different at the latch side. Record the side, the visible fasteners and any missing wipe segment. Do not conclude that the latch needs adjustment.
Case 2 — scrape at hinge end: Capture the hinge-side location and whether the rubbing begins only during swing. A different door-motion path can mimic a tall sweep. Do not turn hinges or change a closer to investigate.
Case 3 — new sweep installed, rub begins immediately: Compare photos of the old and new retaining bases, blade count and location of contact. A nominal width printed on a replacement packet describes stock length, not approved downward projection or mounting geometry.
What a supplier or installer needs from you
Send the door/assembly identity, whether it is rated or a required exit, photographs of the full bottom edge, carrier interface, threshold profile, the specific rub side, and the original/installed sweep reference if genuinely documented. Ask which manufacturer-approved sweep and mounting location maintains the required closing/egress function; do not request “a shorter one” on appearance alone.
Limits: This is non-invasive symptom mapping, not a clearance standard, a code compliance opinion or permission to trim, bend, drill or readjust a door. No manufacturer-specific SKU, current bulletin or numerical installation tolerance has been verified for this article. If operation is obstructed or the door is rated, obtain authorized professional assessment.