Door Sticks at the Top Corner Only After New Floor Installation: Cross-System Decision Tree
Why this matters
A door that sticks only at the top corner after a new floor installation is a cross-system problem. The door itself is almost never at fault. The new floor raised the effective reference plane the door swings against, and the door-frame geometry did not adjust to match. Three distinct mechanisms produce the same symptom - binding at the top hinge-side corner - but each requires a different fix. Planing the top of the door when the actual cause is a threshold height issue removes material unnecessarily and does not solve the problem. Working through the decision tree in order avoids an irreversible cut.
Background: how floor height changes door geometry
A door swings on an arc defined by the hinge center and the door length. The bottom of the door traces that arc just above the floor surface. When the floor surface rises - because a new material is thicker than the old one - the bottom of the door contacts the floor earlier in its swing arc. The door cannot complete its swing, and the frame or door top binds at the point of maximum stress, which is typically the top corner on the hinge side.
The three mechanisms below produce this binding at the top corner through slightly different paths, and the diagnostic question for each is whether the binding happens early in the swing, at mid-swing, or only at the threshold crossing.
Step 1: observe exactly when and where binding occurs
Open the door fully and close it slowly while watching and listening.
Does the bottom of the door scrape or contact the floor surface at any point during the swing?
- Yes, the door bottom contacts the floor surface during the swing - this is floor-contact binding. Go to Step 2A (floor contact path).
- No, the door swings freely until it reaches the threshold or door stop - this is threshold-height binding. Go to Step 2C (threshold path).
Does the door swing freely but then the top corner catches the frame or the door stop as the latch side approaches the strike?
- Yes, door swings freely but catches near fully closed - the door may be deflecting under its own weight as it contacts the new floor at the latch end. Go to Step 2B (deflection path).
Step 2A: floor contact path - door needs undercutting
The door base is contacting the new floor surface because the door was originally undercut (or left at factory length) for the old, thinner floor and was not re-undercut when the new material was installed.
Measure the clearance between the door bottom and the new floor at the center of the door width with the door at rest:
- Clearance is less than three-eighths of an inch - the door needs undercutting to restore clearance.
- Clearance is already adequate at rest but the door still drags - the door may have a slight bow or warp causing the bottom center to drag even when the ends have clearance. Check by sighting down the bottom edge. If bowed, address the warp before undercutting.
To undercut the door: remove the door from the hinges. Mark the cut line on both faces. Use a circular saw with a guide fence for a straight cut, or a hand plane for small amounts. Sand the cut edge smooth and seal the raw wood end grain immediately to prevent moisture absorption.
After undercutting, rehang the door and test the full swing before confirming the fix.
Step 2B: deflection path - floor contact on latch side causing top-corner bind
The door swings freely through most of its arc but the latch-side bottom corner contacts the new floor just before the door reaches the strike. As the door bottom catches, the door deflects slightly, and the top hinge-side corner presses into the frame rabbet, producing the characteristic top-corner stick.
Confirm this cause by watching the latch-side bottom corner specifically as the door approaches the strike. A visible scrape mark on the new floor near the door stop position confirms this mechanism.
Fix: undercut the door as in Step 2A. The latch-side contact is the root cause; once the door clears the floor on the latch side, the top-corner deflection stops.
Additional check: also inspect the hinge screws. When a door deflects repeatedly, hinge screws can work loose and allow the door to sag, which worsens the top-corner bind. Tighten all hinge screws before rehang. If screws spin freely, the pilot holes are stripped - fill with wood toothpicks and wood glue, let dry, and re-drive the screws.
Step 2C: threshold path - new threshold height catches the door bottom
The door and its swing arc are unchanged. The new threshold - the transition piece between the door base and the new flooring material - is taller than the old one, and the door bottom contacts the threshold face on the hinge side of the swing, which is a different contact point than mid-swing floor contact.
Verify by checking whether the door bottom visibly contacts the threshold, not the floor surface, at the binding point.
Options in order of preference:
Adjust the threshold. Many thresholds are adjustable in height via screws on the top surface. Lower the threshold until the door clears it by at least one-eighth of an inch while still making a weathertight contact at full close.
Replace the threshold with one of lower profile. If the installed threshold is a fixed-height type and cannot be adjusted, a lower-profile threshold of the same width may be a direct swap.
Undercut the door. If the threshold height is fixed and non-adjustable and a replacement is not available, undercutting the door is the fallback. Remove only enough material to clear the threshold by one-eighth of an inch - do not over-cut, as this increases the gap under the door beyond weatherstripping coverage.
Do not plane or trim the top of the door for this cause. The top-corner bind is a symptom of the threshold contact at the bottom; removing material at the top does not address the contact point.
Step 3: verify the repair
After any fix, run the full door cycle five times:
- Door swings smoothly from fully open to fully latched with no scraping, dragging, or catching.
- Latch engages the strike without lifting or depressing the door.
- Door closes fully and the weatherstrip at the bottom makes contact across the full width.
If the door latches but the strike plate now appears misaligned (latch hits above or below the strike hole), adjust the strike plate position vertically to match the new door rest position before finishing the job.
References
- Door undercut clearance standards for finished floor materials of various thicknesses
- Threshold height adjustment procedures for common residential threshold types
- Hinge repair for stripped pilot holes in wood door frames