You know the door. Maybe it is the hall bathroom, maybe the back bedroom that faces the side yard. Every summer it starts to drag on the frame, you lean a shoulder into it, and somebody in the family suggests taking it off the hinges and planing the edge. Then the rains come, and by February it closes with one finger again.
That on-and-off rhythm is worth paying attention to. In a lot of Chula Vista homes, a door that changes with the seasons is reacting to moisture moving in and out of clay soil near the foundation. Most of the time it is a nuisance, not an emergency. But the pattern tells you something, and a few months of simple notes will tell you a lot more than one frustrated afternoon with a hand plane. Our sticking doors and windows page covers the basics; this post is about reading the yearly swing.
Our rain comes in one short season
Chula Vista is dry most of the year and wet for a few months. The Western Regional Climate Center’s long record for the Chula Vista station shows a mean of about 9.74 inches of rain a year. December through March brings roughly 6.9 inches of that, so around seven of every ten inches fall in those four months. June through September, added together, averages less than a third of an inch.
That matters because clay soils respond to water. When clay dries, it shrinks. When it soaks up water again, it swells. Ground that goes through a long dry spell and then a short wet one can move a little twice a year, and the edges of a house feel it first because that is where the soil dries out and wets up fastest.
Bentonite beds and graded pads
The California Geological Survey describes the Otay Formation in this part of the county as sandstone with siltstone and claystone, and notes that much of the claystone is light-gray bentonite in beds up to about a meter thick. Bentonite is the kind of clay that swells a lot when it gets wet.
That does not mean your house sits on raw bentonite. Chula Vista’s grading code, CVMC 15.04.055, says that when expansive soil turns up within two feet of finished grade in a cut, or three feet in a fill, in a building area, it has to be removed and replaced with compacted non-expansive soil, unless the City Engineer accepts a different foundation or slab design from a soils engineer. Many tracts in EastLake, Otay Ranch and Rolling Hills Ranch were built on graded pads, and many use post-tensioned slabs, a design the state residential code (R403.1.8) points to the building code for when soils are expansive.
The County’s 2023 hazard plan annex for the city rates expansive soil as widespread but low as a disaster hazard. Put plainly, it is a slow, everyday kind of problem. It cracks drywall and binds doors. It rarely makes headlines.
Rule out the easy stuff first
Before you blame the ground, give the door itself a fair hearing. Plenty of summer sticking has nothing to do with the foundation.
- Hinge screws. Open the door and lift the knob side. If the top hinge moves, the screws have loosened. Longer screws into the framing often fix it.
- Paint and weatherstrip. Thick paint on the edge, or a new weatherstrip, can make a door bind when the air is humid.
- Wood movement. Solid wood doors swell a little with humidity. That usually affects every door of the same type, not just one corner of the house.
- Strike plate. If the latch misses the hole but the door edge is not rubbing, the strike may just need moving.
If one of these fixes it for good, you are done. If the binding comes back next summer, keep reading.
Keep a door diary for one year
This is the part we ask neighbors to do before they call anyone. It costs nothing and it is the most useful thing you can bring to an evaluation.
Pick the two or three doors that bother you most. For each one, once a month, write down:
- Where it rubs. Top corner on the latch side? Bottom on the hinge side? Mark the spot on the frame with a pencil tick and the date.
- The gap at the top. Close the door and look at the space between the door and the head of the frame. Is it even, or does it taper like a wedge?
- Whether it latches. Note if you have to lift or push to make the latch catch.
- What the weather did. “Dry month,” “first big rain,” “irrigation on three days a week.” Rough notes are fine.
- A photo. Same angle every time, with the date showing.
After a year you will see one of a few shapes. A door that tightens from about June to October and relaxes after the first good rains, in a rough cycle, fits the seasonal clay pattern. A door that gets a little worse every month and never comes back is a different story.
Wedge gaps and the drying edge
When the soil along one side of a house dries more than the soil under the middle, that edge can drop slightly. When it gets wet again, it can lift. Door frames sit inside walls that ride on that slab or footing, so a small movement shows up as a wedge-shaped gap at the top of the door, or a rub at one corner.
Look at where your problem doors are. If they cluster along one wall, especially one with lawn on the other side, a hot western exposure, or a planter bed that gets watered heavily, the edge of the slab on that side is a good suspect. Our post on sprinklers, planters and slab edges goes deeper on that wet-edge, dry-edge problem.
Pair the door diary with a look at the walls. Diagonal cracks running up from the corners of that same door, or drywall tape lines that open and close with the season, point the same direction.
Fixes that help, and fixes that hide things
Steadier moisture at the edge of the house is the first thing to work on. Keep irrigation consistent through the summer rather than flooding the beds once a week. Make sure downspouts carry water a few feet away from the wall, and that soil slopes away from the foundation instead of toward it. Fix leaking hose bibs. These small habits often take the sharpest edges off the yearly swing.
Planing a door is fine if the frame is square and the door simply swelled. But if your diary shows a wedge gap that changes with the season, shaving the door in August can leave a big gap in February. You are fixing the symptom at its worst point. Adjusting the hinges or strike is usually kinder, because you can move it back.
One caution for many east-side homes: if your garage or utility slab has a “post-tension” or “do not cut” stamp, do not drill or cut into the slab to chase a problem. Tendons under tension run through it. Our post-tension slab repair page explains why that work needs a plan first.
Signs the pattern is more than seasonal
Call for a closer look if you notice any of these:
- Doors that stop returning to normal in winter, or that get worse each year.
- Cracks in the floor tile or slab with one side higher than the other.
- Floors you can feel sloping, or a marble that rolls the same way in several rooms. See uneven floors.
- Gaps opening where the house meets the patio, garage or pool deck.
- Exterior stucco cracks that line up with the problem doors inside.
None of these means a disaster. They mean the movement is worth measuring with tools instead of a pencil tick.
Bring your notes to a Free Quote visit
If your diary shows a steady seasonal swing and nothing else, the answer is often better water management and patience. If it shows a trend, an evaluation can measure floor levels, check the soil and drainage around the problem side, and sort out whether the slab, framing or something else is moving. We coordinate with licensed engineers as needed when the findings call for design work, and we explain what drives scope, such as access, soil report findings, drainage changes and any permits, without guessing at numbers before anyone has looked.
We serve the whole city of Chula Vista, from the older west-side streets to the newest east-side villages. When you are ready, bring your door diary and photos and request a Free Quote. For background on how clay behaves under homes here, see our expansive soil foundation repair page and our month-by-month crack log.