The outside corners of concrete foundations, steps, and patios are vulnerable to damage. But you can create a crisp new corner in just a few minutes.
First, mix up a thick batch of cement. Add only enough water to hydrate the powder. Next, place a flat steel trowel against one wall, flush with the damaged corner. Scoop up some fresh cement with a 4- or 6-inch-wide drywall knife and pack it into the corner. Keep the trowel tightly pressed to the wall until the missing corner is completely filled with new cement.
Smooth out the patch with the knife, then remove the trowel by slowly sliding it away from the corner. Don’t lift it up, or you’ll pull out the new cement.