Your interior door has a wide gap at the top of the hinge side and rubs against the frame on the latch side. What is the most likely cause and the correct first repair to try?
AThe door is warped and needs to be replaced
BThe top hinge screws are loose or stripped — replace one with a 3-inch screw reaching the stud
CThe door frame has shifted and needs to be re-plumbed
DSeasonal wood expansion — sand the latch-side edge
Uneven gap (wide at hinge top, rubbing at latch side) is the signature of a sagging door caused by loose or stripped hinge screws. One 3-inch screw driven through the jamb into the structural stud pulls the hinge and the top of the door back into alignment. This is a 15-minute fix. Replacement and re-plumbing are expensive, rarely necessary repairs — the vast majority of sagging doors have this simple cause.
Question 2 Multiple Choice
You spray WD-40 on a squeaky hinge and the squeak stops — but three months later it's squeaking again. Why?
AYou didn't apply enough WD-40; a heavier coat is needed
BWD-40 is a solvent and water displacer that evaporates rather than a lasting lubricant
CThe hinge pin is worn out and must be replaced
DWD-40 only works on exterior hinges exposed to weather
WD-40 stands for 'Water Displacement, 40th formula' — it is a solvent and penetrant, not a long-term lubricant. It temporarily reduces friction but evaporates, leaving the metal surfaces dry again within weeks or months. Silicone spray or white lithium grease applied to the hinge pin and barrel provides lasting lubrication that doesn't evaporate.
Question 3 True / False
A door that sticks most summer almost certainly needs to be replaced or largely re-hung.
TTrue
FFalse
Answer: False
Seasonal sticking is caused by wood expansion in humid months — wood is hygroscopic and swells when it absorbs moisture. The fix is light sanding or planing along the binding edge, removing just enough material to restore clearance. The door will likely fit perfectly again in dry months when the wood contracts. Full replacement is unnecessary and wasteful for this problem.
Question 4 True / False
Replacing a short hinge screw with a 3-inch screw can fix a sagging door because the longer screw reaches through the jamb into the structural stud behind it.
TTrue
FFalse
Answer: True
Standard short screws bite only into the thin door jamb casing — minimal holding strength that loosens over years of use. A 3-inch screw passes through the jamb and anchors in the framing stud, which is solid structural wood. This dramatically increases holding strength (the same principle as using proper wall anchors versus drywall screws alone) and pulls the tilted hinge back into correct alignment.
Question 5 Short Answer
Before doing any repair, how should you diagnose what is wrong with an interior door, and what are you looking for?
Think about your answer, then reveal below.
Model answer: Close the door fully and inspect the gap between the door edge and the door frame (the jamb) all the way around. A well-hung door has an even gap — roughly the width of a nickel — on all sides. Uneven gaps reveal the problem and its location: a wide gap at the top of the hinge side combined with rubbing at the latch side indicates sagging from loose hinges. Rubbing along the latch edge that worsens in summer suggests seasonal wood expansion. The gap pattern tells you both what is wrong and where to focus the repair.
This diagnostic step is the key to efficient repair — it prevents guessing and applying the wrong fix. Once you can read the gap, most interior door problems become immediately obvious and the appropriate repair follows directly.