Can you slabjack a house foundation instead of using piers?

What slabjacking a house actually does

Slabjacking, also called mudjacking, lifts concrete by pumping a slurry under it. The Foundation Performance Association (FPA), a Houston engineering group, defines mud jacking as lifting a foundation "by pressure injecting a slurry composed of sand, fly ash, or topsoil and cement between the slab and the soil"^[1]. HomeGuide notes that mudjacking and slabjacking are two names for the same process^[3].

On a driveway or walk, that is the whole job. A house slab is different. It carries walls, a roof and often thickened grade beams under the walls. FPA describes typical foundation leveling as jacking the grade beams at the low areas up until they are level, then re-supporting them. It adds that leveling "may also include the injection of grout or foam under the low areas"^[1]. In other words, grout under a house slab is often one part of a pier repair, not a stand-alone fix.

The core problem: it is a shallow repair

FPA lists the ways a mud jacking repair can fail. The first two are the ones that matter most for a house^[1]:

• "If the soil moisture content changes, the slab can move."
• "This is a shallow repair system effected by active moving soil."

The grout sits right under the slab, in the same soil that shrinks and swells with rain, drought, sprinklers and leaks. If that soil caused the settlement, the soil is still there after the lift. FPA also lists broken sewer or water pipes under the slab, trees close to the slab, extreme seasonal moisture changes and poor drainage as failure causes^[1].

HomeGuide says the same thing in consumer terms. It calls mudjacking "a cost-effective method for minor dips" that "may require follow-up repairs if soil conditions remain unstable"^[2]. Its mudjacking page says a proper job lasts 5 to 10 years or longer, depending on soil and drainage, and that longevity depends more on fixing the cause of settlement than on the mudjacking itself^[3].

Slabjacking vs piers for a house

	Slabjacking (mudjacking)	Piers (steel, helical, concrete)
Where support comes from	Grout just under the slab[1]	Deeper soil or bearing strata, below the active zone where designed that way[1]
Affected by seasonal soil moisture	Yes, it is a shallow system[1]	Less, if deep enough; shallow piers can still move[1]
Stops heave	No	Common repair piers are not tied to the grade beams and cannot stop uplift[1]
Typical use on a house	Small, local low areas, or grout under the slab after pier leveling[1][2]	Settlement of the perimeter or interior grade beams
Cost signal	1,500 sq ft foundation: $4,500 to $9,000[2] or $6,000 to $13,500[3]	See slab foundation repair cost

The two HomeGuide pages, both dated November 2025, give different numbers for the same 1,500 sq ft foundation job^[2][3]. HomeGuide's foundation repair guide lists "mudjacking or slab jacking" at $4,500 to $9,000 (February 2026)^[4]. Treat these as rough national signals, not a quote.

Neither method fixes heave. FPA states that the repair piers most used on Houston-area homes "cannot prevent foundation uplift due to heaving soils"^[1]. Grout pumped under low areas cannot either. See heave vs settlement before you choose any method.

Install risks under a house

FPA's failure list for mud jacking also includes problems caused during the work^[1]:

• Over-injection. "Failure to control the amount of mud injected can cause upward bulging or cracking of the concrete slab."
• Blowouts from excessively high pressure.
• Uneven lift when mud gets trapped by tree roots, pipes or unknown objects.
• Plugged pipes. If underground lines have holes or cracks, grout "may possibly enter the holes and fully or partially plug the lines."

That last one is a big deal under a house, where sewer and supply lines run under the slab. Ask whether a plumbing test will be done before and after the lift. See plumbing tests before foundation repair.

Two more practical points. Interior injection means drilling through flooring, and HomeGuide notes mudjacking holes are 1.5 to 2.0 inches across^[3]. And some house slabs are post-tensioned, with steel cables under high tension inside the concrete. Anyone drilling a post-tensioned slab should locate the cables first. See post-tension slabs.

Who should decide

FPA's guidelines for judging foundation movement are written for use by or under the responsibility of licensed professional engineers^[6]. A single sloping floor is not proof of movement either: FPA notes most residential slabs are built within 1.0 inch of level, so one survey with no baseline cannot prove the slab moved^[6].

Local rules may also decide it for you. Houston requires a permit for foundation repair, which it defines to include "stabilizing a structure that has moved from its originally constructed design." For slab-on-grade houses, the permit needs plans from a Texas-licensed engineer showing the location, quantity and type of piers or pressed piles^[5]. Check your own city before work starts.

A reasonable order:

1. Get an independent engineer's evaluation with an elevation survey.
2. Find and fix water sources: leaks, gutters, grading.
3. Let the engineer say whether a local grout lift is enough or the house needs piers.
4. Get a written scope that says which areas will be lifted, how much, and what the warranty excludes.

Myth: "Slabjacking permanently fixes a sinking foundation"

You will see slabjacking sold as a cheaper, permanent alternative to piers. FPA's own failure list says otherwise: it is a shallow repair, and the slab can move when soil moisture changes^[1]. It can be the right tool for a small, stable low spot. It is not a substitute for deep support when the soil keeps moving.

When to call a pro

• New wall cracks, sticking doors or sloping floors inside the house: call a structural engineer before you price any lift.
• A contractor recommends slabjacking the house without an engineer's report: get an independent opinion.
• Water under the slab, a high water bill or a sewer smell: call a licensed plumber first.
• Any repair your city treats as foundation repair, which may need a permit and engineer plans.