Crack in the Wall: When It's Cosmetic and When It Isn't

You noticed a crack running out from the corner of a doorway, or a thin line above a window that wasn't there last year. Now you're wondering whether it's nothing or whether it's the start of something expensive.

The short answer: the large majority of wall cracks in a home are cosmetic. Hairline cracks that follow a drywall seam, radiate from the corner of a door or window, or show up in a newer home during its first few years are almost always ordinary settling and seasonal movement. What matters is the crack's width, direction and whether it's changing. Here's how to read yours, and how to patch the harmless kind so it doesn't come back in six months.

First, Read the Crack

Look at three things. Width: anything you could slide a dime into (roughly 1/8 inch or wider) deserves a closer look. Hairline is reassuring. Direction: vertical and horizontal cracks along drywall seams are usually just the seam tape letting go. Diagonal cracks stepping up from a door or window corner at roughly 45 degrees are worth watching. Movement: write today's date next to the crack in pencil and mark each end with a light tick. If it hasn't grown in a few months, it's stable.

Also check whether the doors and windows nearby still work normally. A crack with no other symptoms is a very different thing from a crack in a room where the door has also started sticking.

Fixes to Try, Cheapest First

1. Leave a stable hairline alone until you're painting (0 minutes). If it's thinner than a hair and hasn't moved, there's no urgency. Fold it into the next time that room gets painted.
2. Patch a seam crack with mesh tape and compound (30 minutes, plus drying). Scrape the crack open slightly with a utility knife so the compound has something to grip, vacuum the dust, then bed self-adhesive mesh tape over it and skim on joint compound with a 6-inch knife. Feather the edges wide. Two thin coats beat one thick one every time.
3. Sand, prime and paint (30 minutes, next day). Sand smooth with 120-grit, prime the patch so it doesn't flash through, then paint. Our paint touch-up guide covers matching sheen so the repair disappears instead of announcing itself.
4. Use flexible caulk where materials meet (15 minutes). Cracks where drywall meets trim, or along a ceiling line, will reopen no matter how well you mud them, because two different materials are moving at different rates. Paintable latex caulk flexes and holds.
5. Repeat once if it reopens (30 minutes). A crack that comes back in the same spot once isn't alarming. A crack that comes back twice is telling you something is still moving, and that's your cue for the next section.

When to Stop and Get Someone Else to Look

Stop patching and have a structural engineer or foundation specialist take a look if you see any of these: a crack wider than 1/8 inch, cracks stepping diagonally from several door or window corners at once, a horizontal crack across a garage or basement wall, doors and windows that have started binding along with the cracks, or a crack that is visibly wider than it was a few months ago. Cracks that appear after an earthquake also deserve a professional read, even if they look minor.

None of that means bad news is coming. Parts of San Diego County sit on clay soils that expand and shrink with moisture, and homes in 92127 and 92128 built on graded pads do settle. But it's worth knowing what you have before you spend money covering it up. An engineer's opinion is cheap compared with guessing.

Let Our Team Handle the Cosmetic Ones

Taping, mudding, sanding, priming and painting a crack properly is three visits' worth of drying time and a lot of dust for something that takes a pro under an hour of hands-on work. For Livd members, your dedicated handyman can patch the cosmetic cracks on a regular visit, and because it's the same handyman each time, they'll notice if one of them quietly comes back.

Already a Livd member? Add "wall crack repair" to your task list in the Livd app and we'll take care of it on your next scheduled visit.

Not a Livd member yet? Schedule your free home walkthrough at livdhomes.com. We'll look at what your home needs and build a proactive maintenance plan to keep the little things from becoming big ones.