Why Doors and Windows Stick During Foundation Movement
Doors and windows sit in frames - rectangular openings in the wall framing. When a foundation moves differentially, the framing above distorts: what was a perfect rectangle becomes a parallelogram. The door or window, still rectangular, no longer fits the distorted opening properly.
The most common presentation:
- A door that binds at the top corner opposite to the direction of settlement
- A door with a gap at the bottom on one side and tight at the top on the other
- A door that used to latch without effort but now requires force to click shut
- Diagonal cracks in the drywall at the corners of door and window openings
How to Distinguish Foundation Sticking from Other Causes
| Characteristic | Foundation-Related | Seasonal/Other |
|---|---|---|
| Multiple doors affected | Common | Unusual |
| Diagonal cracks at corners | Common | Uncommon |
| Developed suddenly | Yes, often | Often seasonal |
| Present year-round | Yes | Often resolves |
| Correlates with other symptoms | Yes | No |
| One door only | Less common | More common |
| Interior vs. exterior doors | Both | Often exterior only |
Interior doors are more reliable foundation indicators than exterior doors. Exterior doors are exposed to weather - swelling, warping, and frame settlement are common non-foundation causes. Interior doors in conditioned space don’t have that excuse.
The Diagonal Crack Test
A highly reliable companion to foundation-related sticking: look at the upper corners of the door or window opening. If you see a diagonal crack in the drywall or plaster running at 45 degrees from the corner, the framing has racked - distorted from a rectangle.
This crack pattern - called a “45-degree crack at a corner” - is caused by shear stress in the drywall as the framing moves. It’s a strong indicator of differential foundation movement.
What Happens If You Ignore Sticking Doors
Foundation movement doesn’t self-correct. If the cause is differential settling, the distortion will worsen over time:
- Door frames will distort further, eventually preventing the door from closing at all
- Cracks at the corners will widen and propagate into the wall surface
- Other structural elements (windows, wall-to-ceiling transitions) will develop similar symptoms
- The same forces distorting door frames are also stressing plumbing connections, especially in slab-foundation homes
Immediate Actions
- Note which doors are affected - all of them? One or two? Interior or exterior?
- Look for diagonal corner cracks at affected openings
- Check your floors for slope - set a marble or ball on the floor in the affected area
- Check when the sticking started - sudden onset vs. gradual worsening
- Get an inspection if you have: multiple affected openings, diagonal corner cracks, any other foundation symptoms, or the sticking developed suddenly
A foundation inspection ($200-$500) will tell you definitively whether you’re looking at a foundation issue or a simpler framing and moisture problem.