If cracks are climbing up the brick from the corners of your garage door, or the brick above the opening looks like it's starting to sag, the problem is usually a piece of steel you can't see: the lintel.
That's the short answer, and it's right most of the time. But it isn't the whole answer, and the part that gets left out is the part that decides what the repair is.
Cracks above a garage door come from one of two things: the steel lintel carrying the brick across the opening is bending, or the footing under the opening has settled. A garage opening is the longest unsupported span on most houses, so it shows movement before anywhere else, and the repairs differ.
What a lintel is, and why it fails
The lintel is the steel beam that spans the top of your garage door opening and carries the weight of all the brick above it. It sits out of sight, so most people never think about it, right up until it starts to fail. When it does, the brick it was holding up has nowhere to go but down and apart, and that shows as cracking above the door.
Picture an L-shaped piece of angle iron running the full width of the opening with a course of brick sitting on its lip. Everywhere else on your house, brick sits on the footing and the ground carries it. Over the garage, it hangs on that one piece of steel, and the steel has to be fastened back into the framing behind it to stay straight.
When it isn't fastened well enough, or the span is long and the brickwork above it is heavy, the steel starts to give. The owner has watched it happen on new work: "That metal will sag in a 2-day period, probably a quarter inch with nothing even on. That's with 18-footers." The specific install defects behind that are laid out on the garage lintel repair page.
Why the garage cracks before anywhere else
Look at your house and count the openings. A window is three or four feet across. An entry door is three. A two-car garage is sixteen or eighteen feet, and on a lot of houses there's a second story of brick sitting on top of it.
That makes the garage opening the longest unsupported run of wall you own, carrying the most weight, held up by the least. So when anything moves, it shows there first. That's also why a crack over the garage doesn't automatically mean the rest of the house is in trouble. It means you're looking at the weakest spot in the wall, which is exactly where you'd expect the first crack to appear.
Is the steel dropping, or is the ground dropping?
This is the fork, and it's worth working through before anyone comes out, because the two problems get repaired differently.
Where the crack starts
A lintel problem starts at the opening. The cracks begin at the top corners of the door or in the brick course directly above it, and they spread outward and upward from there. The middle of the span is the lowest point, because that's where a bending beam sags most.
A footing problem starts at the ground and works up. The crack tends to run from a lower corner of the garage wall diagonally upward, and the whole corner of the wall goes with it rather than just the courses over the door.
Sight along the top of the opening
Stand at one end of the garage wall and look along the brick course right above the door, the way you'd sight down a board. A bending lintel shows a shallow dip with the low point near the middle.
A settling footing usually tilts the whole opening instead. One end sits lower than the other and the brick courses run slightly downhill in one direction across the entire wall, not just over the door.
Check the inside of the house
This is the most useful check on the list. Go into the room behind or above the garage and look for cracks at door and window corners, and at whether the floor feels like it runs toward one wall.
A lintel is holding up the brick veneer. It isn't holding up your house. So a lintel problem generally stays outside, in the brick. When the drywall inside is cracking on the same side of the house, or the floor above the garage runs downhill, the movement is coming from underneath, not from the steel.
The owner's version of this test runs the other direction and is worth knowing: "if the sheetrock's not cracked, if your floor is down and your block aren't cracked along the way, the floor's never moved. It was built that way." Not everything was built perfect, and a floor that's been a half inch out since 1978 isn't news.
It can be both
On a two-car garage with a column between the doors, a settling column and a sagging lintel show up together, and one is pulling the other along. That combination is covered on the garage lintel repair page, because it's a different repair again.
What happens if the steel keeps bending
This is worth understanding, because it explains why one crack turns into four.
Steel that has started to bend keeps bending. As it drops, it doesn't only go down, it pushes outward against the brick on both sides of the opening. Here's how the owner describes what that does: "It pushes the walls out more laterally, so the wall ties start snapping more. More of them start snapping. Then the wall starts to come out at you. Then more bricks start to crack."
Wall ties are the small metal straps that hold your brick veneer back to the framing. Once enough of them let go, the brick beside the opening starts leaning out toward the driveway on its own, which is a second problem sitting on top of the first. There's more on that in why brick pulls away from the house.
None of that happens overnight. It's the reason a crack that's been the same width for two years is a different conversation from one that's opened up since spring.
Your garage door stopped sitting square
Plenty of people notice the door before they notice the crack. It catches on one side, the gap along the top looks wider at one corner than the other, or the opener starts reversing because the door isn't meeting the floor evenly.
When the steel over the opening drops in the middle, the opening is no longer a rectangle, and a rigid door in a racked opening binds. That's a structural symptom showing up as a door symptom, which is why it gets misread so often.
The distinction that matters: a garage door company handles the door, the springs, the tracks and the opener. If the door itself is fine and the opening it sits in has changed shape, adjusting the door is going to have to be done again.
And the doors and windows inside
Two things send people looking at their garage, and sticking doors is the other one. Both belong in the same diagnosis.
When it's the weather
Wood swells when the air is wet. In a Georgia summer a wooden door or window tightens in its frame, sticks a little, and loosens back up when things dry out. If it's mild, it affects one or two doors, and it comes and goes with the season, that's the wood breathing.
When it's the house
Settlement sticking behaves differently. A footing drops, the wall above it racks slightly out of square, and the frame that used to be a rectangle becomes a shallow parallelogram. The door hasn't changed. The hole it lives in has.
What tells them apart:
- The gap around the door is uneven, tight at one corner and wide at the opposite one
- A crack runs at an angle out of a door or window corner
- The door drifts open or swings shut by itself because the frame is off level
- More than one door or window is affected, and they're on the same side of the house
- It keeps getting worse instead of easing off when the weather turns
The last one is the giveaway. Humidity comes back every year and then goes away. Settlement only goes one direction.
Why houses move here
There's a story you'll see on nearly every foundation site in Georgia: red clay swells with rain, shrinks in drought, and heaves houses around. The USDA soil survey says otherwise. Around here that clay is rated low for exactly the kind of seasonal movement people blame it for. Dense, yes. Restless, no.
The real culprits are water and what the ground was made of before anybody poured concrete on it. Soil that was filled and never properly packed. Buried debris left in the lot. A grade that tips back toward the house and holds water against it. When one of those sits under a garage corner, everything stacked above it follows the footing down.
A garage corner is a reasonable place for that to happen, because it's usually where the driveway sheds its water and where a downspout comes down. Enough hard rain running into the same spot will wash a hollow out under a footing that looked solid when the house was built.
What a settling garage corner looks like when it's fixed
When the ground is the cause, the repair goes under the corner rather than into the steel. Here's a customer describing that version of it:
"My foundation at the entrance to my garage had settled significantly over the lifetime of my home, causing the brick facia to crack in multiple directions. Anglin Did a great job, correcting the settlement and closing the cracks In the facia. I don't think I could've asked for a better match were they tech pointed the remaining crack in the masonry. Everything done was done with the great attention to detail at a very reasonable prize. I would definitely use them again and recommend them to other folks."
P J, 5 stars
Cracks in multiple directions, at the entrance to the garage, from a footing that went down over decades. That's the second branch of the fork, and it's a different job from lifting a bent lintel.
What to check before you call
Four things, none of which cost anything:
- Mark the ends of the crack with a pencil and write the date on the brick. In a month you'll know whether it's moving or just sitting there.
- Sight along the brick course above the door from one end of the wall and note whether it dips in the middle or tilts to one side.
- Walk the room behind or above the garage and look for cracked drywall at door and window corners on that same side of the house.
- Watch that corner during the next hard rain and see where the water from the driveway and the downspout actually goes.
Those four answers are most of the diagnosis. Whoever comes out is going to ask you the same questions.
Frequently asked questions about cracks above the garage door
What is the lintel above a garage door?
It's the steel beam, usually a length of L-shaped angle iron, that spans the top of the opening and carries the brick above it. It's bedded into the mortar so you only see its edge, and it has to be fastened back into the wood header behind it to stay straight under the load.
Why do cracks show up over the garage before anywhere else on the house?
Because the garage opening is the longest unsupported span in your walls and it carries the most brick. Sixteen or eighteen feet of wall is hanging on one piece of steel, while everywhere else the brick sits on the footing. The weakest spot cracks first, which is what you'd expect.
Does a crack above the garage door mean my foundation is bad?
Often it doesn't. A bending lintel is a brick veneer problem with nothing wrong underneath it. The thing that points at the foundation instead is agreement elsewhere: cracked drywall inside on the same side of the house, a floor that runs downhill, or brick courses tilting across the whole wall rather than dipping over the door.
Why did my garage door stop sitting square in the opening?
When the steel over the opening sags, the opening stops being a rectangle and the door binds against it. The clue is the gap along the top being wider at one corner than the other. The door and its hardware are a garage door company's work, but the shape of the hole it sits in is a structural question.
My doors and windows stick every summer. Is that a foundation problem?
Probably not if they loosen back up when the air dries out, since wood swells with humidity and metro Atlanta gives it plenty. Settlement sticking doesn't come and go. It affects several openings on the same side of the house, comes with angled cracks at the corners, and keeps getting worse.
Is a hairline crack in the mortar over the garage worth worrying about?
Not on its own, and not this week. Mark both ends with a pencil, date it, and look again in a month. A crack that hasn't moved and has nothing else in the house agreeing with it is usually just a mortar joint. One that has widened, or that now has a dip in the brick above it, is the one to have looked at.
Find out what's holding up your garage
A mason can stand in your driveway, sight along the brick over the opening, look at where the crack starts and whether anything inside agrees with it, and tell you whether the steel is bending or the ground moved. That answer changes the repair, so it's the thing to get first.
Anglin's has been setting and repairing steel over Atlanta openings since 1930, and the same crew that lifts the header closes the brick back up.
Call 770-422-2924 for a free look.