By Lance McCarthy
You are sitting there at the dinner table when you see it. There on the wall above the doorway. A crack! (Cue that violin screeching noise they use in the movies for when spiders or knives are shown) Why is it there? Is the house collapsing? Should you evacuate to the back yard? What do you do?
There are lots of things that can crack in a house, for lots of reasons. In short, something is moving. Could be harmless, could be a sign of something common, or could be pointing to something worse.
Here’s a quick checklist on diagnosing yours–and knowing if you should worry.
Above a doorway or opening? Maybe worry. This is probably due to the foundation settling. Try placing a level on the floor in the opening. If it is out of level, something below is moving.
Is it a straight line, and can you see the outline of drywall tape? Don’t worry, but call the contractor. This usually means whoever finished the drywall didn’t properly adhere the tape to the drywall, and it is coming loose now.
Are there water stains in that area? Worry. Water is always something to take care of quickly where it touches a wall.
Is it in a corner or a joint? Don’t worry. This probably means the humidity level is fluctuating in the house too much, and the wood is expanding and contracting more than the paint can keep up. Try using Shermax, Elastomeric paintable caulk from Sherwin Williams. It will cover the gap better.
Is it between the trim and the wall? Don’t worry. Does the trim move when you push on it? That means it wasn’t fastened tight enough. If it doesn’t move, this may be a sign of the house settling, or of the humidity issue we talked about.
Is the tile cracking? Worry. That takes a pretty strong force. It usually means there is something allowing the surface below the tile to move. If you have the house is settling too much, it is probably related. If not, the rest of the tile may be soon to follow.
Is it a grout joint? Maybe worry. If it is in a corner, that probably means normal grout was used in the corner instead of a siliconized grout caulk. Corners in a house flex (by fractions of an inch) as a house warms up, or a strong wind hits one side. Grout is stiff and can’t handle that flex. A siliconized caulk is more pliable and will last much longer.
If it is not in a corner, this can mean the tiles are moving more than they should, or that the grout didn’t “stick” right there as well as it should.
Probably don’t worry. It is rare that I go into a house that is more than 30 years old and don’t see slight gaps in the hardwood floor. Wood is hygroscopic (meaning it attracts and holds water molecules). Especially as you move from warm months to cold months and back again, the floor will inevitably grow or shrink (in small ways).
Concrete and Brick
Is it in the wall? Is it an angle crack? Probably don’t worry. It is getting pounded from the wet/dry soil outside, and just showing its battle scars. Is it a straight horizontal crack? Worry. Call a structural engineer to check it out.
Is it in a concrete slab? Did it happen soon after the concrete went in? Don’t worry. It is probably just the result of the concrete drying a little too quickly. All concrete slabs crack. The installer usually cuts control joints into new concrete to help those cracks happen where we want them to.
Hope that helps. If you have a particularly pesky or curious crack in your house, let me know or send me a picture. I’d be happy to help diagnose!
Do you have questions about this space or others? Just reach out to me at firstname.lastname@example.org.