Something caught your eye. A crack above a door, a window that fights you, a floor that feels like it tilts toward one wall. Now you're standing there wondering whether these are signs of a real foundation problem or just a house getting older.
Here's the useful thing to know up front: one sign on its own is usually nothing. It's when several show up together, in a pattern, on the same part of the house, that they start to mean something.
One sign of a foundation problem is usually nothing. Several together, on the same side of the house, is the pattern worth acting on. Diagonal cracks at the corners of doors and windows, doors that quit latching, and a floor that runs downhill in the same direction point at a footing that has moved.
Start at the top, not in the crawl space
Most people's instinct is to go look under the house. The crews here do the opposite, and the reason is worth understanding.
In the foreman's words: "First, you look at the top, on the first floor, and then you come down underneath it. You can find out where they're settling. From the top." And later, plainly: "You gotta start at the top, use your level, whatever you need to do, and then get underneath it and figure out why did it do that."
The floor above tells you *where* the house dropped. Getting underneath tells you *why*. Do it the other way around and you're looking at joists and posts with no idea which one matters.
The marble test, and what it actually tells you
You've probably heard of rolling a marble across the floor. It's a real test, and the crews see homeowners do it.
Here's how the foreman describes it: "the homeowner sometimes has actually gone to the extent of saying, hey, I pulled my laser level out, and we've got this over here, or I put a marble over here, and the marble's going to the area where the laser's pulling."
What makes it useful isn't that the marble moves. Every floor in every house has some slope. What matters is whether it always runs to the same place, and whether that place lines up with the cracks you found outside. That's a pattern. A marble that drifts a little differently in every room is just an old floor.
Try it in two or three rooms and note which way it goes each time.
What kind of crack is it?
Cracks come in shapes, and the shape is most of the diagnosis. These are the ones the office hears described every week.
Stair-step cracks in brick or block
A crack that climbs diagonally through the mortar joints, following the brick pattern. This is the classic settlement crack. Something under that stretch of wall has dropped.
Diagonal cracks at door and window corners
Drywall cracks running at an angle from the upper corner of a door or window frame. Openings are the weak point in a wall, so when a house racks, that's where it shows first. The service page calls a diagonal crack a telltale sign of settling, and it is.
Horizontal cracks
A crack running straight across a basement wall, usually a block wall, often with the wall bowing inward above it. This one is pressure from outside rather than settlement from below, and it belongs in a different conversation. Worth knowing: poured concrete walls settle and crack, but they rarely bow. As the owner puts it, "I've never seen one bow. Block wall usually is the one bowing."
Vertical cracks
Straight up and down, hairline, often near the middle of a wall. These are frequently shrinkage from curing and the least likely of the four to mean movement. Date it, watch it, and see whether it grows.
It might not be your foundation at all
This is the part most articles skip, and it's the part that saves people money.
A sloping or bouncy floor can come from the framing rather than the ground. The foreman is direct about it: "not all sagging floors are over a crawl space. It may be a legit, normal basement that you put your cars in, and that span from those 4-inch metal poles that you see are too far apart, and that main beam is sagging because it just was too far. It's always usually because of the span issue."
There's a second version of this that's common in older metro Atlanta houses, and it has nothing to do with the ground. Kitchens got heavier. A 1970s floor framed for carpet and a modest kitchen is now carrying a stone island, a tile floor and a wall of new cabinets. The joists didn't fail; the job changed. That's covered in why floors sag.
Cracked brick can also be its own thing. Brick veneer is hung on the house with metal ties, and when those rust through the brick can separate with no foundation problem behind it. That's covered in why brick pulls away from the house.
Why houses move here, and what it usually isn't
You'll read constantly that Georgia red clay swells and shrinks and heaves foundations around. It's worth knowing that the soil data doesn't support it. The USDA rates the clay under most of metro Atlanta as low for shrinking and swelling. It's dense, not expansive.
What actually moves a footing here is water and what the ground was made of before the house went on it.
Water with nowhere to go
The owner's own list: "Uncompacted soil, trash pit. Very negative slope that retains water, so the porch will drop, the footing will drop, the brick will drop, the wood will drop, and the roof will drop." A grade that falls back toward the house, a downspout emptying at the corner, and a few of the downpours we get will wash a hollow out from under a footing.
Ground that was filled rather than cut
Much of the metro sits on lots that were graded, cut and filled when the subdivision went in. Fill that was packed only on top looks like solid ground and behaves like anything but. On newer construction the owner is blunt about the pace: "that's all they're doing, building slab houses all over the place. And I can guarantee you they're not packing that dirt."
A small cause under a big symptom
It doesn't take much. Describing one job: "About the size of the kitchen table. That was the problem... Caused a 10-foot diameter sinkage. Everything pulled toward the area."
The sign you noticed may not be the whole story
Worth going in with your eyes open: people usually call about one thing and find out it was part of something larger. A customer describing their first visit:
"I moved into a house that was built in the 1970's. My initial call was for the front porch which was sinking when I moved in. I called Anglin's, and was able to get an appointment that week with their estimator. While at the house, Gus gave me an inspection of the rest of my house and found that one side of the house was also sinking."
Judy Woodall, 5 stars
That's also the argument for looking sooner rather than later. Caught early, the repair usually needs fewer piers.
What to do before you call
Four things, none of which cost anything:
- Date the crack. Mark each end with a pencil and write the date on the wall. In a month you'll know whether it's moving or just there.
- Photograph it with something for scale, a coin or a tape measure held against it, so you can compare later.
- Run the marble test in a few rooms and note whether it always goes the same way.
- Walk your downspouts and your grade after a hard rain and see where water sits against the house.
If the crack hasn't moved in a month and nothing else in the house agrees with it, you've probably learned what you needed to know.
Frequently asked questions about foundation problems
How do I know if a crack is serious?
Shape, width and company. Stair-step cracks in brick and diagonal cracks at door corners point to movement. A crack you can fit a coin into deserves attention. Most of all, a crack that has other symptoms agreeing with it, on the same side of the house, means more than one sitting by itself.
Are hairline cracks in drywall normal?
Usually, yes. Houses shift and settle as materials cure and seasons change, and thin vertical cracks that stay the same size are ordinary. The ones to watch run at an angle from a door or window corner and keep growing.
What happens if I wait?
The house keeps doing what it's doing, and the repair generally gets larger. Caught early, the fix may need fewer piers than the same problem caught two years later. It is not an emergency you need to solve this week, and it is not something that resolves on its own.
Do all foundation problems need piers?
No. Some of what looks like foundation trouble is framing, span or brick veneer, and none of those call for piers. That's why figuring out what moved comes before anybody quotes a repair.
My home inspection flagged a foundation crack. What now?
Get it looked at rather than guessing, because a buyer's inspector will write up what they see without diagnosing it. Having a straight answer in hand, including if the answer is that it's cosmetic, is worth a lot during a sale.
Will fixing the foundation close the cracks in my brick?
Often, yes. When a footing is lifted back to position, the brick above it goes with it, and the remaining cracks get pointed and matched as part of the same job rather than left for a separate trade.
Find out whether it's really your foundation
You shouldn't have to guess at this from your driveway, and you shouldn't have to pay to find out. Someone can walk the house, look at where the cracks run and which way the floor goes, and tell you plainly whether the ground moved or something else did.
Anglin's has been doing this in metro Atlanta since 1930. If the answer is that your footing moved, foundation repair is what comes next.
Call 770-422-2924 for a free look.