How to Tell If That Crack in Your Wall is Really a Problem

How to Tell If That Crack in Your Wall is Really a Problem
Photo: zimmytws, Shutterstock

Cracks in your wall can inspire a sense of impending doom, especially if your home is relatively new. Is it just a cosmetic blemish that a little spackle can fix? Or are you about to be buried in rubble?

The good news is that most cracks are pretty superficial and easy to fix, so there’s probably no need to evacuate your family when you spot a hairline crack on a wall. The bad news is that some cracks can indicate serious problems that you’re going to have to deal with, and the solution is probably expensive. Here’s how to tell which scenario you’re dealing with.

What direction is the crack in your wall?

The first thing to note is the direction of your crack. Thin, straight vertical cracks in drywall or plaster are typically the least problematic, as they’re almost always the result of the house “settling” — a catch-all term that describes the shifting of a home’s structure over time. Newly constructed homes tend to settle more dramatically: the foundation can sink slightly, and the wood used in framing can dry out, causing it to shrink a tiny amount. If the house isn’t occupied all the time — for example, a summer home that’s locked up eight months out of the year — the lack of climate control can lead to cracks as well.

These sorts of cracks can be easily repaired and shouldn’t alarm you — in fact, if your house is brand new then you should probably wait a year before even bothering to repair them, because you’ll likely see a few more as the house settles into its final position.

Level, horizontal cracks are also usually not too concerning. If they’re thin and appear right where two drywall joints meet, it’s probably just crappy taping. Drywallers often skimp on the joint compound (or “mud”) when they’re in a rush, which looks fine at first but can cause the tape to pull away from the joint, causing a thin horizontal crack. The repair involves either re-taping the joint or possibly gluing the tape down and doing a quick spackle and paint job over it.

If your crack runs at an angle, is a jagged lightning bolt, or combines both horizontal and vertical cracks in a step-stair pattern, that can indicate a more serious problem. These sorts of cracks should be inspected by an engineer and repairs should be planned as soon as possible.

How big is the crack in your wall?

Another factor in determining how much to worry about cracks in your walls is their size. Measure the width of the crack. Generally speaking, anything less than a quarter-inch wide is probably — probably! — not a huge concern. It’s likely a “stress crack,” due to the aforementioned settling or other minor shifts in your structure. If it’s wider than that, it can indicate a more dramatic change, especially if the crack is relatively recent as opposed to a crack you inherited from the previous owner twenty years ago.

Where is the crack located?

Finally, the location of the crack matters. Cracks lining up with drywall joints, as mentioned, are probably no big deal. Similarly, thin cracks that appear around doorways and windows likely aren’t serious either. Because windows and doorways interrupt the wooden studs of your walls, they have a lot of extra framing around them to maintain load-bearing capacity and structural integrity — which also increases the likelihood of some superficial cracking as things settle. Even cracks at an angle in these locations may not be a big problem. If your doors and windows still operate smoothly without sticking and there’s no obvious warping (if your door doesn’t have a weird gap at the top or bottom, for example), it’s probably just a stress crack.

Discoloration and nail pops

One last thing to note is whether your crack features yellowish or brownish stains. If so, it’s very likely caused by water infiltration. Small amounts of water will drip down until it can’t go anywhere, then soak into your drywall or plaster, weakening it. Even if you’ve never noticed water, a stain can indicate it was there.

The good news? This crack will be easy to fix. The bad news? You’re going to have to figure out where the water is coming from, or else the damage will return. If the water infiltration has been happening for a long time, you’re going to have to check for mould and rotted framing as well.

Another sign of water infiltration or other problems are what are called “nail pops,” when the heads of nails or screws holding your walls together start to emerge, initially showing up as bumps on your wall and possibly eventually breaking through. Nail pops by themselves are minor issues caused by shrinking wood, but if they appear alongside a crack then you might have a larger issue. If the screw or nail has broken through the wall, inspect it for rust — a sign of a water problem.

Cracks in your walls don’t necessarily indicate your house is falling down around you, but it’s always best to take a good, hard look at them before dismissing them as cosmetic. And if they do indicate a bigger problem, don’t delay in getting a structural engineer to inspect the place. Better to be reassured the crack is nothing than to wake up with a brand new, unplanned open-air living room.

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