Slab leveling FAQ: what to ask before you commit
Concrete leveling can fix a sunken slab, but it is not a universal solution. These are the questions homeowners most often ask—and the honest answers you need before comparing proposals.
What does concrete leveling actually mean?
Concrete leveling (also called slab jacking or mudjacking) raises a settled slab by pumping material beneath it to restore its elevation and alignment. It repositions concrete that is otherwise intact; it does not repair structural damage or crumbling concrete. If the slab itself is badly cracked or spalled, leveling alone may not be appropriate.
Is my slab a good candidate for leveling?
Leveling is suitable when the slab is structurally sound but uneven—for example, a step at a joint or a tilted corner. It is not appropriate if the concrete is severely cracked, if there is active erosion, or if the subgrade has failed. An on-site assessment by a qualified professional is the only reliable way to determine suitability. See our methods & limitations page for more context.
Why do quotes for the same job differ so much?
Quotes vary because each contractor evaluates the slab differently: the number of injection points, the material used, access constraints, and whether drainage or base work is included. A written scope of work is essential for comparing apples to apples. On-site assessment determines the final price, not a phone estimate. Never rely on a price given without seeing the slab.
Will leveling make the cracks disappear?
No. Leveling raises the slab to level; it does not fill or hide existing cracks. Hairline cracks may become less noticeable after the slab is level, but wide or structural cracks will remain visible. Do not expect leveling to cosmetically erase cracking—it addresses elevation, not surface damage.
Can I judge the problem from photos alone?
Photos can show the surface condition, but they cannot reveal the cause of settlement, the condition of the subgrade, or whether drainage is actively washing out soil. A qualified professional must inspect the site to understand why the slab moved and whether leveling will last. Photos are a starting point, not a diagnosis.
How should I compare proposals from different contractors?
Compare written scopes, not just prices. Look for what each proposal includes: number of holes, material type, access plan, and any drainage or base work. Use our estimate comparison checklist to structure the comparison. A lower price may omit necessary steps—ask each contractor to explain their scope in writing.
What role do drainage and ongoing movement play?
Drainage that directs water under a slab can cause soil erosion and repeated settlement. If drainage is not addressed, leveling may be temporary. Ongoing movement—cracks that widen or new steps appearing—indicates an active cause that must be evaluated before any repair. Our repair vs. replacement guide explains when deeper evaluation is warranted.
Should I ask about safety and structural issues?
Yes. Ask the provider to explain whether the slab is structurally sound, whether there are signs of subgrade failure, and whether leveling is appropriate or if replacement is needed. A qualified professional should be willing to discuss these concerns and recommend the right course. If you have any doubt, get a second opinion.
