How to Repair Broken Concrete Stair Corners

The corners of concrete steps are the most vulnerable part of the stairs and the most likely to crack and crumble over time. Hairline cracks on either the vertical or horizontal surfaces will allow water and possibly salt to get into the cracks and breakdown the corners. Luckily, fixing the corners and edges of concrete stairs is a job that homeowners can take on by themselves.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Ready mix concrete
• Wooden float
• Work gloves
• Small sledge hammer
• Bricks or wooden stakes to hold form boards in place
• Plastic sheeting
• Concrete bonding agent
• Wheelbarrow or concrete mixer
• Eye protection
• Cold chisel
• 1-by-4-inch lumber for form boards

Fixing the Corners and Edges of Concrete Steps

1. Remove all the loose and crumbling concrete from the edge. Use a cold chisel and a small sledgehammer to break off any loose pieces and get rid of them.

2. Prepare some "form boards" out of 1-by-4-inch lumber. The top of the form board will be lined up level with the edge of the step, and it should be slightly longer than the damaged section.

3. Spread clean motor oil on the form boards. This will prevent the concrete patch from sticking to the board. Then install the board with the top edge even with the top of the step.

4. Hold the form board in place with a couple of bricks or stones (if it's on the front edge), or by driving a wooden stake into the ground and fastening it to the form board (if the repair is along the side of the step).

5. Paint the area to be patched with a concrete bonding agent (available at home stores). This acts like glue and helps the concrete patching material bond or join to the old concrete.

6. Prepare a batch of ready mix concrete patching material in a wheelbarrow or concrete mixer while the concrete bonding agent is "setting up." Follow the manufacturer's directions to ensure that you get the right consistency.

7. Use a wooden float to firmly pack the concrete patch material into the area to be repaired, and smooth the surface even with the top of the form board.

8. Allow the concrete to set for about 30 minutes and then use an old broom, a whisk or a stiff paintbrush to create a slightly rough surface on the patch to help prevent slips.

9. Cover the patched area with a sheet of heavy plastic or a tarp and leave it in place for a few days--just removing it once a day to spray the patch with a mist of water. This will ensure the concrete dries slowly. If concrete dries too fast, it will crack.

10. Wait a week, remove the form board and bricks, and admire your new, crisp and clean concrete corners and edges.

Tips & Warnings

• You can help prevent the edges of your stairs from cracking by applying a concrete sealer (available at home stores) once a year. Fall is a good time since you will likely have water from snow melting and freezing on your stairs during the coming winter months. Concrete sealer will also help prevent any salt damage.
• Washing your stairs with a mild solution of TSP and warm water (in the spring) will get rid of salt residue.
• Be sure you always wear proper eye protection when chiseling loose concrete. You just don't know where the tiny concrete chips will go.