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Cracks in the slab: foundation crack repair
Most Frisco houses sit on a concrete slab poured on the ground, and most slabs have cracks. The question is not whether yours has one. It is whether the two sides of the crack are still moving.
What it looks like
Where slab cracks show themselves
- Across the garage floor, the one place the bare slab is on view.
- Down the exposed edge of the slab outside, as a vertical line in the strip of concrete below the brick.
- At an outside corner, where a wedge of concrete has split off under the brick. Builders call this a corner pop.
- Through tile or wood flooring, in a line that follows a crack in the concrete beneath.
Three things are worth noting about any of them: how wide it is, whether one side stands higher than the other, and whether it has changed since you first saw it.
Other causes
Cracks every slab has
Concrete shrinks as it cures. Thin, flat cracks with both sides level are the normal result and are often decades old.
A corner pop comes from brick and concrete expanding at different rates in the sun. It is a surface break at the corner, separate from the slab's strength.
The Texas engineers guidelines put it plainly: cracks may weaken concrete, but most cracks do not compromise structural integrity.
At the inspection
What a company checks
Width and offset. A crack you can slide a coin into, or one with a step across it, gets attention that a hairline does not.
Whether the crack carries through to the slab edge and lines up with cracks in the walls above.
Floor elevations on both sides. If the slab bends at the crack, the survey shows it.
Whether the slab is post-tensioned, meaning steel cables were tightened inside the concrete after it was poured.
If it needs repair
What foundation crack repair might involve
Injection. Epoxy injected into a crack is meant to restore stiffness across it. Where the aim is only to keep out moisture or insects, a flexible sealant may be used instead.
Underpinning. If the crack exists because one part of the slab has dropped, sealing it changes nothing. Piers under the dropped part come first.
Cable work. On a post-tensioned slab an engineer may have the cable forces tested and slack cables re-tightened.
In the meantime
Two things to avoid
Do not let anyone cut, core or drill into a post-tensioned slab without locating the cables first. If you know your slab is post-tensioned, say so on the phone.
Do not pour filler into a crack before it has been looked at. Width is evidence, and filler hides it.
Slab crack questions
Is a hairline crack in my garage floor a foundation problem?
A photograph cannot establish whether a crack needs repair. Mention widening, a step between the two sides, nearby brick cracks or sticking doors when you arrange an inspection.
Can a slab crack be repaired without piers?
Sometimes. If the slab has stopped moving, a crack may be injected or sealed and left. If the slab is still dropping on one side, the crack will reopen until that side is supported.
Foundation repair in Frisco and nearby
Describe the problem, book the inspection
This number is for foundation repair on houses. Say where the cracks are, which doors stick and how long it has been going on. If part of the house shifted all at once, there is a gas smell, or brickwork seems about to come down, clear the house and dial 911 or the gas utility before anything else.
Ready to have someone look at it?
Phone and say what you have noticed. The foundation repair company on the other end is independent of this site and takes on houses in your part of Collin or Denton County. Ask it for a time to come and inspect.
Call (972) 430-3959Your call may be recorded. Read how referrals are paid for and what happens to call details.