Cracks are often par for the course when it comes to basement walls. Your home’s foundation is comprised of rigid materials that can crack when they expand and contract with temperature changes or experience pressure from a settling foundation. Other cracks form as a natural consequence of the concrete curing process. Most cracks in basement walls don’t threaten a home’s structural integrity, but it’s a good idea to repair even small ones, which can otherwise allow unwanted substances—like water or radon gases—to enter.
Patching small cracks
Small cracks in a basement wall are typically relatively simple to patch. While you can make the repair using an ordinary cement mix, a vinyl concrete patch offers an elastic bond that is stronger and longer-lasting than regular concrete. Like concrete, vinyl concrete patch kits consist of a dry powder that must be re-hydrated with water—or, for a more durable bond, a special latex liquid—but vinyl patches (not surprisingly) also contain vinyl; this helps the patch effectively seal cracks using less material.
To ensure the vinyl patch adheres properly, clean the crack and the area surrounding it. Use a wire brush to remove loose concrete bits, remnants of old fillers and paint from the crack and the area surrounding it. Then use a shop vacuum or soft bristle brush to clean up dust and smaller debris. Working in small batches, mix the patch ingredients according to package instructions. Apply the material to the crack in a smooth layer with a putty knife, feathering it out away from the crack, and allow the patch to cure.
How to repair larger cracks
Repairing larger cracks is a considerably more involved process. There are a variety of DIY basement wall crack fillers on the market, including polyurethane foam and hydraulic cement products, but opt for an epoxy-injection kit for a lasting solution. Start by cleaning dirt and debris in and around the crack. Then follow the kit instructions to apply the injection ports and sealing compound along the length of the crack. Next, beginning in the bottom port, inject the crack with the epoxy and continue moving upward, plugging each port as you go. Once the epoxy cures, saw the neck off of each port.
For more permanent, guaranteed crack repair, though, it’s best to hire a professional to handle this job. There are other circumstances that call for professional help, too. For example, while minor cracks in basement walls are normal, others may compromise your home’s structural integrity. If you notice large, deep or numerous cracks, or if the cracks run horizontally along the wall, hire a structural engineer to determine whether your home’s foundation is at risk of serious damage.