How to Level a Slab Foundation: A Comprehensive Guide

March 4, 2024

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A level foundation is critical for the structural integrity and longevity of any home. If you live in a house built on a slab foundation, maintaining its level is essential to prevent severe issues from arising. 

Signs like uneven floors, cracked walls, or doors that won't close properly could indicate that your home's slab needs leveling.

This comprehensive guide will explain the essential steps and considerations for leveling a slab foundation.

Remember, this guide for how to level a slab foundation is not so that you can try to complete this work yourself. We want you to know what to expect when working with a professional foundation repair company.

cracked slab foundation on home in Dayton

Understanding Slab Foundations

Slab foundations are constructed by pouring a single layer of concrete directly on the ground, essentially making the foundation and floor one unit. This design is common in warm climates as it doesn't require a basement or crawlspace. 

While generally durable, slab foundations can shift over time due to soil movement or issues like expansive clay soils.

Telltale Signs Your Slab Foundation Needs Leveling

If you notice any of the following signs, it's time to consider leveling your slab foundation:

  • Uneven or sloping floors
  • Cracks in interior or exterior walls, especially diagonal cracks
  • Doors or windows that stick or won't close properly
  • Visible cracks in the concrete slab itself

Addressing these issues promptly can prevent more significant and costly structural problems from developing and the need for slab leveling.

Common Causes for Slab Leveling and Repair 

Leveling slab foundations often reveals underlying issues that contribute to the initial settling or unevenness. Some common challenges include:

  • Poor Soil Conditions

Expansive clay soils that shrink and swell with moisture changes can wreak havoc on slab integrity over time. Foundation repair professionals may need to stabilize problem soils through methods like soil grouting or installing root barriers.

  • Plumbing Leaks

leak in slab concrete foundation

Undetected plumbing leaks can lead to significant soil erosion beneath the slab, causing voids and settlement. Leaks must be repaired, and eroded areas filled/compacted before releveling can occur.

  • Structural Damage

In severe cases, the slab itself may be too damaged from cracking or settling to be releveled effectively. This could require partial or complete slab replacement by a structural engineer.

  • Drainage Issues

Improper drainage around the home's perimeter allows moisture to saturate and destabilize the soil supporting the slab edge. Regrading and installing proper drainage is key.

Having professional slab leveling and repair experts involved allows for accurate assessment and implementation of targeted solutions beyond basic mud-jacking or slab-jacking to remediate the root causes.

Preparing for Leveling a Slab Foundation

A thorough foundation inspection is important before starting the leveling process. Identifying the root cause of the unevenness, such as soil settlement, expansive soils, or even plumbing leaks, will guide your approach. 

Additionally, gather necessary tools and materials like hydraulic jacks, self-leveling compounds, and reinforcement materials.

How to Level a Slab Foundation: Step-by-Step

While leveling a slab foundation may seem doable as a DIY project, it's highly recommended to seek professional assistance, especially if you lack the necessary experience or expertise. Even minor mistakes can compromise your home's structural integrity.

Working with slab repair professionals ensures the job is done safely, efficiently, and per local building codes. They have the knowledge and equipment to properly identify and address underlying issues like soil conditions or structural deficiencies.

If you decide to level the slab yourself, proceed with extreme caution and consider these typical professional steps:

Step 1: Inspection and Assessment

inspector evaluating foundation repair in Ohio

Inspect the slab carefully to identify uneven areas requiring leveling. Look for cracks, signs of settlement, or other damage needing repair. Consult professionals if unsure about assessing the extent of issues.

Step 2: Preparation

Ensure you have all necessary tools, materials, and safety gear like hydraulic jacks, self-leveling compounds, reinforcement materials, hard hats, and steel-toed boots.

Step 3: Elevation

Using hydraulic jacks at key points, carefully elevate the settled slab areas following professionals' guidance on proper lifting techniques to avoid additional cracking.

Step 4: Void Filling

Once elevated, fill any voids under the slab with a cement-based compound or polyurethane foam to provide a stable base and prevent future settlement.

Step 5: Reinforcement

In severely settled areas, professionals may recommend installing piers, supplemental beams, or other reinforcements beneath the slab for added support.

Step 6: Leveling and Finishing

Apply a self-leveling compound over the raised areas to create an even, smooth surface. A professional concrete finisher can ensure a proper, durable finish.

Slab Leveling Methods and Techniques

house with slab foundation that requires leveling

There are several techniques that foundation repair professionals may utilize to level a settled slab foundation, depending on the severity of the issues and underlying causes. Common leveling methods include:

Mudjacking/Slab Jacking

One of the most widespread methods, mudjacking or slab jacking involves pumping a cement grout or slurry mixture beneath the sunken section of slab. The grout fills voids and provides a stabilized base to lift and level the concrete back into position.

Polyurethane Foam Leveling

This technique uses structural grade polyurethane foam that is pumped underneath the slab to fill voids and lift it back to level. The expanding foam can be extremely effective, especially for more significant voids.


In cases of severe settlement or unstable soil conditions, piering may be recommended. This involves installing support piers deeply into load-bearing soil or bedrock and connecting them to the slab to transfer the home's weight off the poor soils.

Slab Bolstering

For very badly settled sections, professionals may bolt supplementary steel beams alongside the affected areas of slab and use jacking against these braces to lift and stabilize the slab.

Complete Slab Replacement

If the existing slab is too severely damaged by cracking or differential settlement to be effectively releveled, a structural engineer may prescribe removing and completely replacing portions or all of the slab foundation.

The appropriate leveling approach depends on factors such as the size/location of settled areas, underlying soil makeup, and drainage issues.

Qualified foundation repair professionals can evaluate and recommend the most viable, cost-effective solution tailored to your home's specific leveling needs.

Maintenance Tips Post-Leveling

Once your settled slab foundation has been successfully leveled and stabilized, ongoing maintenance is key to prolonging its new levelness:

  • Ensure drainage systems, such as downspout extensions and grading slopes away from the home, direct water flow away from the slab's perimeter.
  • Promptly repair any plumbing leaks to prevent soil erosion and washout under the slab, which can lead to resettlement.
  • Avoid planting trees or shrubbery too close to the foundation, as this can lead to soil desiccation from invasive roots as the plants mature.
  • Regularly inspect the slab, both inside and out, for new cracks, unevenness, or signs of settlement that could indicate the need for further repairs.
  • In problematic soil conditions, periodic soil grouting or stabilization injections by professionals may be recommended to maintain solid soil compaction.

By staying watchful about drainage, plumbing, landscaping effects, and the slab's condition, you can catch potential settlement issues early before they escalate into major structural problems.

For ongoing preventative maintenance, it is advisable to work with a reputable foundation repair company.

When to Call a Foundation Professional

foundation repair company in dayton oh

While some slab foundation aspects can be DIY'd, such as minor crack repairs, it's best to involve professionals if you encounter significant slab damage, structural concerns, worsening settlement after initial leveling attempts, or the need for specialized soil stabilization solutions.

At the first sign of issues, be sure to reach out to a certified and licensed foundation repair contractor or foundation repair company in your area.


Maintaining a level slab foundation is crucial for safeguarding your home's value and structural integrity. By understanding the process and partnering with qualified professionals when needed, you can properly level your settled slab and prevent future, more costly damage.

Remember, addressing foundation issues promptly is key to extending your home's lifespan.

Making sure your home is level and stable is too important to leave to chance. Call the team at Dayton Foundation Repair Experts to get the job done right!

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