What Is Foundation Spalling? Foundation spalling is the spalling of surface concrete that typically occurs on crawl space or basement walls, but can also occur on concrete slab Foundation spalling is usually easier by visually inspecting the foundation as it occurs on the concrete surface. How Can You Fix Foundation Spalling? It's relatively easy to repair once your foundation has confirmed the load-bearing capacity of your foundation and no basement walls or reinforced concrete slabs are needed. First loosen concrete, rose and rubble with a wire brush. The booster should then be treated to prevent rust. Finally, a re-peeling - concrete mix - should be applied to all affected areas with a spatula or trowel. The solution must remain moist during the hardening process in order to ensure that the connection with the existing concrete is as strong as possible.