First, make sure the slab is part of the foundation
Pavement guidance describes road slabs. It does not establish which repair is suitable for a house foundation.
This guide is about structural support and movement, not plumbing diagnosis.
Lifting or restoring contact below a slab
Slab jacking means placing grout or another flowable material below concrete to fill a void and raise a settled area. Federal pavement guidance explains the basic mechanics and also warns that lost support can return if the underlying condition is left unresolved.
That guidance helps explain how lifting works, but a road slab is not a house foundation. It cannot show that lifting is suitable for a particular home. Ask which loads, soil conditions, damage, and access limits the evaluation covers.
When deeper support is a different repair
Some proposals use piers to transfer load past weak near-surface soil. Helical piers turn into the ground; other deep-support elements use different installation methods. Their depth, capacity, placement, and connection to the structure are engineering questions.
Lifting and deep support may change elevation, but that does not make them the same. One approach may fill a void or raise concrete. Another creates a new load path into deeper soil. A clear proposal should state which problem it addresses.
What an evaluation needs to sort out
The evaluation may consider where movement appears and how the slab and walls are built. Ask what can be observed about the slab, walls, soil, and drainage, and what remains concealed.
Water near the foundation can affect soil and support conditions, but drainage trouble does not prove why a slab moved. Correcting runoff may be part of protecting the site while a separate structural plan addresses support.
Questions for a slab repair proposal
Ask whether the plan is meant to lift, level, stabilize, transfer load, or repair concrete. Ask what observations support that goal and how the result will be checked. Confirm whether plumbing, utilities, permits, engineering, or inspections fall outside the contractor’s scope.
A proposal should also explain its limits. Find out what may remain uneven, what happens if hidden damage appears, and who is responsible for design decisions. If the cause or structural effect is unclear, a qualified on-site evaluation is the sensible next step before choosing the product or system.
Sources and evidence
- The Rehab Guide, Volume 1: FoundationsU.S. Department of Housing and Urban Development · Accessed
Supports: Historical foundation and slab repair categories; pier load transfer; engineering evaluation boundaries
The Rehab Guide, Volume 1, June 1997: section 8, printed pages 40-42. Historical high-level taxonomy only; no current code, dimensions, installation directions or property-specific suitability.
- Concrete Pavement Preservation Guide, Second EditionFederal Highway Administration · Accessed
Supports: slab stabilization mechanics; slab jacking mechanics; loss of support; cause correction; method limitations
Government technical guide inspected only for general concrete slab lifting/support mechanics. It covers pavements, not residential foundation suitability.
- Stormwater Gutters DownspoutsU.S. Department of Energy Building Science Education · Accessed
Supports: roof runoff; grading; downspouts; foundation saturation
Inspected technical page supports exterior water-management categories.
- Building Inspection PolicyNational Society of Professional Engineers · Accessed
Supports: Engineering evaluation boundary and limits of observational inspection
Position Statement 08-0149, revised November 2024; Position Statement and Background exceptions. Professional policy, not local law or a repair design.