How Foundation Settlement Causes Garage Floor Cracks (Uneven Support, Voids & Repair)

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Are you ready to reclaim your cracked garage floor? 

Whether you use your garage primarily as a parking space, a tool station, or a catch-all for that miscellaneous stuff you haven’t been able to throw away – cracked garage floors are a precarious trip hazard. And, more importantly, garage floor cracks always indicate a deeper issue. One of the most common reasons for garage floor cracks is foundation settlement – when a foundation sinks unevenly, exerting a tremendous amount of force on the garage slab.

Dalinghaus Construction Inc. has been on the foundation repair scene for almost two decades, with over 100 years of combined underpinning and crack repair experience. We strive to educate the world about garage floor cracks, even if you ultimately choose not to repair with us.

This article covers garage floor cracks created by foundation settlement, uneven support, voids, and the best garage floor crack repair options.

Settlement, a Garage Floor Crack Instigator

A common cause of cracked garage floors is settlement. Settlement refers to when a structure sinks/settles into incompetent, non-load-bearing soil. These weak soils are referred to as expansive soils because they expand and contract (often in direct correlation with the level of water saturation). Examples of expansive soil include clay soils and loam soils.  

Expansive soils pose a serious issue to foundations and garage floors (or any structure that wants to remain level). Imagine placing a piece of plywood down on an even surface. You’ll have no issues walking across the board and the structural integrity of the plywood won’t be compromised. However, if you place the same board across an uneven surface and walk across it, the board will wobble or even fracture.

Now, imagine (for the sake of the thought experiment) attaching framing to this plywood board foundation, followed by walls and a roof. The uneven foundation affects the entire structure, resulting in crooked framing, cracked walls, a slanted roof, and so on. The same is true for largescale homes.

Thus, the garage floor (generally a concrete slab reinforced with rebar) cracks under the extreme and prolonged pressure created by settlement.

Other signs of garage floor settlement include:

  •   Sloped garage floors
  •   Garage doors or windows that are difficult to open/close or out of square
  •   Cracks in garage drywall

In addition, settlement signs and symptoms might not only be limited to the garage. To learn about more signs and symptoms, read our article 5 Signs of Foundation Issues.  

Voids Cause Garage Floor Cracks

Settlement and expansive soil can also result in voids. Voids in any capacity are hazardous to structural integrity. Take grain silos for example. Grain silos can have large air pockets hidden beneath the top layer of corn. If a worker decides to walk across the corn, occasionally these air pockets buckle and bury the farmer alive.

Granted, voids beneath your home are not as dangerous as voids in grain silos, but they behave in a similar fashion. Occasionally, a layer of dirt will give way beneath your garage floor, bringing the soil above it crashing down, creating a lack of structural support. The lack of uneven support results in garage floor cracks.

These voids can be filled by polyurethane injection. To learn more about filling garage floor voids via polyurethane, read our article5 Steps to Polyurethane Foam Injection (From Drillholes to Cure).

How to Repair Garage Floor Cracks Created by Settlement

Repairing garage floor cracks caused by settlement is a complicated process. Other garage floor crack repairs are relatively minor in comparison. The vast majority of garage floor crack repair involves epoxy. For example, cracks or spalling instigated by water damage are treated via epoxy. Carbon fiber staples, in addition to epoxy, are used to treat other forms of cracks.

Garage floor cracks created by settlement require more support than simply epoxy or carbon fiber staples. Underpinning, with push pier or steel pier systems, provides support to your uneven garage floor. Push piers and helical piers are like underground stilts that are driven to either bedrock or load-bearing-competent soil. These piers support the weight of the home and provide the option to lift the foundation/garage slab back to maximum practical recovery (or as level as possible).

To learn more about steel pier systems and their implementation process, read our articlesThe 5 Steps to Push Pier Foundation Repair andThe 5 Steps to Helical Pier Installation.

After the affected section of the garage has been fitted with push or helical piers and safely secured, then the garage floor crack can be fixed once and for all with epoxy.

Ready to Have Your Pristine Garage Floor Back?

In this article, we discussed how settlement can cause garage floor cracks and sink your garage slab. We also covered how voids form beneath your cracked garage floor and how to best address garage floor settlement with steel pier systems.

Are you ready to get your garage back? Dalinghaus Construction is here to help you reclaim your space. We’ve serviced thousands of foundations and hundreds of cracked garage floors. We have the expertise and know-how to get you back to working in your garage in no time. 

If you would like to book a free garage floor crack inspection and live in Southern California or Arizona, click the link below.


Brian Dalinghaus

Brian is one of the Co-Founders of Dalinghaus Construction. He has been in the foundation repair industry since 2005. During his career, he has been associated with helping over 4,000 homes and structures throughout California and Arizona.

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