Slab Foundation Crack Repair (Carbon Fiber Staples)

Slab on grade foundations crack and fissure due to a wide variety of causes: foundation settlement, foundation heave, root damage, poor mud mixture, and so on. Cracks are always indicative of a deeper issue. The crack is not the problem; it’s a symptom. Slab cracks can result in significant bulges beneath your carpet, linoleum, or hardwood floors, creating trip hazards. And slab cracks can indicate compromised structural integrity.

While slab cracks might seem like an enigma, Dalinghaus Construction Inc. is here to demystify them for you. We’ve underpinned thousands of homes and fixed countless slab cracks. After decades in the foundation repair business, we can assure you there is a solution. Whether you choose to utilize Dalinghaus or another contractor – we’re here to educate you about slab crack repair.     

In this article, we will cover why slab cracks occur and how to address them. So, let’s dive in.

Slab Foundation Crack Repair

What Causes Slab Foundation Cracks?

As mentioned above, slab cracks are always indicative of a deeper problem. Slab cracks are the signs and symptoms, not the proverbial virus. But this symptom can be tricky to find. The majority of homes do not have an exposed slab throughout the entirety of the house (unless you’re going for a 70’s chic vibe). So, you might not know immediately that there is an issue. Odds are, you’re more likely to trip over the crack than see it first.  

When slab on grade foundations crack, they bulge or bow, resulting in an uneven walking space. It might feel like a concrete tumor has developed underneath your shag carpet, kitchen tile may chip and break, your linoleum flooring may lift upwards. Often a layer of flooring covers and camouflages the crack, flooring which needs to be removed to expose the fissure.

  •   Foundation settlement – The slab on grade foundation sinks and settles into incompetent, non-load-bearing soil (such as loam and clays), exerting stress onto the home’s foundation, framing, and throughout the interior of the home. The uneven support causes the slab to crack, further compromising the structural integrity of the home.

Other signs and symptoms:

  • Drywall cracks
    • Stucco cracks
    • Sloped floors
    • Leaning chimneys
    • Windows and doors that are difficult to open/close  
  •   Foundation heave – The slab on grade foundation is pushed upward by expansive soil (such as loam and clays), driving an incredible amount of force upward. This extreme pressure can crack up and through the slab on grade foundation.
  •   Root damage – Trees, bushes, and shrubbery can sink roots underneath your home’s foundation. As the roots develop and grow, they push against your slab, resulting in some gnarly concrete cracks.
  •   Poor initial mud mix – Incorrectly mixed mud/concrete can result in slab on grade cracks. These cracks tend to be small and hairline, often referred to as crazing.
  •   Concrete spalling – Extreme and chronic moisture can result in water damage/spalling, which can make your foundation more susceptible to slab on grade cracks. Spalling usually results in pitted and “scarred” concrete.  

After the cause of the crack has been determined, an appropriate plan of action can be drawn up. Remember, cracks are a symptom, not the direct issue. Foundation settlement and foundation heave, specifically, will require more than a simple carbon fiber staple repair to fix the cracked slab.

Foundation settlement generally requires steel pier systems (push and helical piers) to secure the foundation to competent, load-bearing soil in a procedure referred to as underpinning. To learn more about underpinning, read our article What is Underpinning (Definition, History, & Types). 

How to Fix Slab Foundation Cracks: Carbon Fiber Staple Repair

After the source of the crack has been identified and dealt with, whether that’s underpinning or addressing a leak, then the repair can begin. For large cracks, carbon fiber staple repair is a great solution. Here are the three steps to carbon fiber staple repair:

Step 1 –

The crack is accentuated to allow for better cohesion between the carbon fiber staples, epoxy, and concrete. This is referred to as “crack chasing.” A grinder is zipped through the cracks, making them deeper and wider to allow enough epoxy to penetrate the crack.

Step 2 –

The carbon fiber staples are implemented in an angled pattern to ensure the crack is held together at multiple divergences. Small puncture holes are drilled into the slab concrete for the ends of the carbon fiber staples. The cross grooves are ground down so that the staples fit flush with the slab foundation.  

Step 3 – 

After the carbon fiber staples have been inserted, they are covered with epoxy. The crack and staples are covered with epoxy, which is scraped flush to the concrete slab. The epoxy dries and the flooring can be reapplied. The carbon fiber staples and epoxy absorb the pressure that use to pull the slab apart, recirculating it through the staples to keep the slab in one piece and crack-free.

Slab Foundation Crack Repair

Foundation Repair

 In this article, you learned about the primary reasons for slab on grade cracks, where to find them, and how to fix large cracks that threaten the structural integrity of your home. Cracks are never the issue; they are the symptom.

Learn more: Why Do I Have Cracks In My Slab If I Have No Foundation Issues?

Dalinghaus Construction Inc. has over 100 years of combined foundation repair experience. We would be happy to offer you a free foundation inspection to determine the source of your slab on grade cracks.

If you live in Southern California or Arizona and would like a free foundation inspection, 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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