How to Repair Spalling Concrete on Walls, Driveways & Slabs

Spalling concrete is a common issue on concrete walls, driveways, and slabs across Toronto and the GTA. What may start as minor flaking or surface damage can quickly lead to deeper deterioration if left unaddressed. This guide breaks down what spalling concrete is, why it happens, and how to repair it properly on walls, driveways, and slabs.

What Is Spalling Concrete?

Spalling concrete occurs when the surface layer of concrete begins to crack, flake, or break away. This damage typically exposes the aggregate beneath the surface and can range from minor scaling to deeper structural deterioration.

Spalling often appears as:

• Chipped or peeling concrete
• Pitted or rough surfaces
• Loose or crumbling areas along edges or faces

While it’s easy to dismiss spalling as simple wear and tear, it’s usually a sign that something deeper is happening within the concrete.

How Spalling Concrete Develops

Spalling is most commonly caused by moisture getting into the concrete and creating internal stress over time. This can happen as a result of freeze-thaw cycles that trap water that then expands and contracts. Additionally, de-icing salts accelerate surface breakdown on driveways and walkways, and improper finishing or curing during the original pour can weaken the surface layer. In some cases, corrosion of embedded steel reinforcement also contributes, as steel expands as it rusts and pushes outward, causing the surrounding concrete to fail.

Why It’s Important to Address Spalling Early

Ignoring spalling concrete can quickly turn what should be a manageable repair into a much larger and more expensive problem. Once the surface layer of concrete is compromised, water is able to penetrate more easily, which accelerates deterioration and can eventually affect the integrity of the structure itself. Addressing spalling early helps prevent ongoing moisture damage, extends the lifespan of concrete walls, slabs, and driveways, improves safety by eliminating uneven or crumbling surfaces, and preserves the overall appearance of a project.

Tools and Materials for Concrete Spall Repair

Before starting any repair, it’s important to have the right tools and materials on hand. Common items used in DIY concrete spall repair include:

• Cold chisel and hammer or angle grinder
• Wire brush or stiff-bristle brush
• Pressure washer or hose
• Concrete bonding agent
• Polymer-modified concrete repair mortar
• Trowels and putty knives
• Concrete sealer

The right tools can make or break a project. Additionally, using the correct repair material is critical. Not all patching products are designed for vertical surfaces or exterior exposure. In the next section, we will talk about how to repair different situations of spalling concrete.

How to Repair Spalling Concrete Walls

Spalling on concrete walls, including foundation walls and retaining walls, often appears as flaking or shallow craters along the surface.

Surface Preparation

Start by removing all loose or damaged concrete using a chisel or grinder. The goal is to reach solid, sound concrete. Clean the area thoroughly to remove dust, debris, and contaminants.

Bonding and Patching

Apply a concrete bonding agent to improve adhesion. Use a polymer-modified repair mortar designed for vertical applications and press it firmly into the repair area with a trowel. Build the patch in thin layers if necessary to prevent sagging.

Finishing and Curing

Smooth the surface to match the surrounding wall and allow the patch to cure according to the manufacturer’s instructions before exposing it to moisture.

How to Repair a Spalling Concrete Driveway

Driveways are particularly vulnerable to spalling due to traffic, moisture, and de-icing salts.

Surface Preparation

Remove all loose material and thoroughly clean the area. For driveways, pressure washing is especially effective. Ensure the surface is completely clean before patching.

Patching the Spalled Areas

Apply a bonding agent, then fill the damaged sections with a high-strength repair mortar suitable for horizontal surfaces. Compact the material well and smooth it flush with the existing driveway.

How to Repair a Spalling Concrete Slab

Concrete slabs in garages, basements, and utility spaces can also suffer from surface spalling.

Prepare the Surface

As with other repairs, remove loose concrete and clean thoroughly. Pay close attention to edges and corners, where spalling often worsens.

Apply Repair Material

Use a repair mortar designed for slab applications. Spread evenly with a trowel and feather the edges to blend with the surrounding surface.

Allow Proper Set Time

Avoid foot traffic for at least 48 hours for light use, and follow product-specific curing guidelines before placing heavy loads on the slab.

DIY Repair vs. Professional Concrete Repair

DIY spalling repairs can be effective for small, shallow areas where the damage is purely surface-level. However, not all spalling should be treated as a simple patch job.

DIY repair may be suitable if:

• The damage is shallow and localized
• No reinforcing steel is exposed
• Moisture intrusion is minimal

Hire a professional if:

• Spalling is widespread or recurring
• Reinforcing steel is visible or corroded
• Structural integrity may be compromised
• Matching finishes or large-scale repairs are required

Professional repair services can properly assess underlying issues and ensure repairs last. If your concrete needs repairing, give kreitmaker a call. We can help!

Long-Term Prevention Tips for Spalling Concrete

Preventing future spalling is just as important as repairing existing damage. Proper drainage away from concrete areas also plays a significant role in long-term durability.

For new projects, using the correct concrete mix for the application and ensuring proper placement and finishing are critical. Precise control over mix design and on-site adjustments can greatly reduce the likelihood of spalling over time.

Concrete Repair Starts with the Right Materials

Whether you’re tackling a small repair or planning a larger concrete project, having the right materials makes all the difference. At kreitmaker, we supply high-quality concrete solutions with same-day delivery six days a week across Toronto, Mississauga, Scarborough, Markham, Vaughan, and beyond. With volumetric concrete trucks, you pay for what you use and get precise control of the mix on-site.

Ready to Get Started? If you’re repairing spalling concrete or planning a new pour, contact kreitmaker to order concrete to get expert advice, or schedule concrete delivery in Toronto and the GTA. Our team is here to help you get it done right.