Doors are the cheapest foundation test you own
A door opening has very tight tolerances. It's square, it's plumb, and it has to stay that way for the door to work. When the house moves even a little, the door is usually the first thing to notice.
That makes it a useful early warning system — and a free one.
Why it happens
When part of a house settles or lifts, the frame around a door racks slightly out of square. A quarter inch of movement at the foundation can translate into a door that drags across the whole width of the opening.
In Middle Tennessee, the most common driver is soil moisture. Expansive clay swells when it's wet and shrinks when it's dry. A wet spring followed by a dry summer can move a foundation enough to matter.
Seasonal vs. permanent
This distinction matters a lot.
Seasonal sticking — the door sticks in late summer and frees up in the fall — usually points to soil moisture cycling. It's worth managing water around the house, but it's often not structural.
Permanent sticking — the door sticks and keeps getting worse, or it sticks in every season — is more concerning. That's movement that isn't reversing.
What to look for alongside it
- Cracks in the drywall at the top corners of the door frame (a diagonal crack is the classic sign)
- A gap that's wider at the top of the door than the bottom, or vice versa
- A floor that slopes toward that door
- The same pattern at other doors on the same side of the house
One sticking door in an old house is usually just an old house. Four sticking doors on the same wall is a pattern.
What I'd check
I look at the door frame first, then the wall above it, then the floor, then under the house. The door tells me where to look. The crawl space tells me why.
What to do about it
If it's seasonal and mild, managing drainage is often the whole fix. If it's getting worse, it's worth having the foundation looked at before you start planing doors down — planing treats the symptom and leaves the cause in place.
