What is Epoxy Injection Crack Repair and Stitch Weld Procedure?

Epoxy injection crack repair is a popular repair method used to seal and bond cracks that develop within concrete slabs. In this article, we will discuss what an epoxy injection crack repair is, how it differs from an epoxy stitch weld crack repair, and which method is best for addressing the type of cracks that might exist in a concrete slab.

The development of cracks in concrete is inevitable. Most cracks that develop within concrete are simply a result of the concrete material drying out and shrinking as it ages and cures. But some cracks can develop as a result of stress, excessive movement, or settlement. When determining if a crack in concrete is in need of repair, it is important to consider the size of the crack and the potential cause of the crack. For cracks that exceed one-eighth of an inch in width (with no evidence of vertical movement within the surface of the concrete along the length of the cracks) and that are suspected to be due to shrinkage of the concrete, a simple epoxy injection crack repair can oftentimes be the best and most appropriate solution. The epoxy injection is further justified if and when there is a need to prevent moisture from entering these types of cracks or prevent moisture from surfacing through the cracks. 

The epoxy injection procedure consists of first opening up (or v-notching) the existing crack using a saw or grinder. A vacuum system is then used to thoroughly clean and remove all dust and debris from the cracks. The appropriate epoxy material (oftentimes a two-part, high strength epoxy resin) is then poured or injected into the cracks. Once the epoxy has dried and cured, the cracks are then bonded and sealed.

When these cracks appear, a transverse crack (or horizontal) is one that shoots across the centerline of the concrete slab laying perpendicular to that line. A longitudinal crack (or vertical) is one that runs along the centerline of the concrete slab. For example, imagine the centerline of a road. A transverse crack will be shown traveling the width of the road, and a longitudinal crack will be shown traveling the length of the road. A transverse crack is pictured below:

Given that this procedure’s objective is to seal a preexisting crack, it is important to point out that the use of this method is not permitted when there are structural issues such as shifting or settlement. An epoxy injection procedure is in no way the sole solution for a slab that is or will experience settlement.

Epoxy Stitch Weld Procedure

An epoxy stitch weld procedure gets its name from its appearance once applied to a crack on a concrete slab. It looks as though the slab had gone through a traumatic experience and had to be stitched up at the doctor. This procedure is used in conjunction with the epoxy injection method to bring an additional level of support to the slab. You can see the “stitch” appearance in the picture below:

The crack shown above is first sanded down with all dust and debris being removed from the area with a shop-vac, and then a grinder is run through the crack to smooth out the edges for seamless installation. Once that is complete, the cross stitch is ground throughout the length of the crack and carbon fiber strips/staples are placed in that groove. These carbon fiber strips hold the slab in place to guarantee a secure hold. Foam tubing or fine-grained sand is then stuffed into the crack to act as a bonding/sealing agent for the epoxy solution. The epoxy solution is then mixed and poured into the crack, with any excess being scraped away until it is flush. Once the solution solidifies, it can be painted or stained over.

The Fortress grid stitch system that is used during the epoxy stitch weld procedure is high strength, low cost, and has a fast installation time. When compared to other types of stitching that do not use carbon fiber rods, the strength of this system has been proven to be 4,000 pounds of more overall strength. When compared to other manufactured materials, these carbon fiber rods are made in America, which cuts the cost of having them shipped in from overseas. This allows for the cost to the consumer to be lower than anywhere else. Installation takes half the time of any ordinary stitch weld procedure, which also translates into lower labor costs.

Like the epoxy injection procedure, the epoxy stitch weld method is not a sole solution for settlement or structural issues, it is merely a crack repairing procedure.

The crack in your concrete slab can cause moisture and water intrusion as well as humidity spikes. An epoxy crack repair procedure is used to seal these cracks once any structural issues are taken care of. For added support to the integrity of the slab, consider an epoxy stitch weld procedure, which, with the use of carbon fiber rods, can give you all the extra support you need. When you have cracks, know that Carolina Foundation Solutions can help fill them.