How to Repair Concrete Stairs

Concrete stairs are able to withstand the rigors of daily use without the constant maintenance worries associated with wood. Unfortunately, moisture will slowly break down the surface of the concrete and cause spalling, or flaking. Ignoring chips, cracks, and dings could lead to serious breaks, requiring reconstruction of the stairs. A little concrete and a trowel will get this repair project underway.

Things You'll Need

• Safety glasses
• Gloves
• Broom
• Circular saw with concrete-cutting blade
• Polymer-modified cement overlay material
• Trowel
• Concrete joint repair mix
• Garden hose
• Portland cement
• Sand
• Shovel
• Two pieces of lumber
• Measuring tape
• Cinder blocks
• Motor oil

Instructions

Spalling and Crack Repair

1. Sweep all dirt and debris from the flaking and cracked area. The goal is to have the repairing material bond to the stairs, rather than dirt or loose concrete.

2. Cut the flaking concrete spot(s) and cracks with a circular saw. Use a concrete-cutting blade. Remove all of the flaking concrete by cutting down through the portion that is still attached to the concrete surface. Use the blade to widen and deepen cracks. They need to be approximately ¼ of an inch wide and ¼ of an inch deep.

3. Mix polymer-modified cement overlay material to repair the areas with spalling, or flaking. Follow the label instructions regarding the amount needed for the particular job at hand.

4. Apply the mixture to the top of the surface using a trowel and smooth over. Let the repaired area cure for 48 hours before allowing foot traffic on the stairs.

5. Mix (or purchase pre-mixed) concrete joint repair material. Fill in the cracks with the joint repair mixture, smooth with a trowel and let cure for 24 to 48 hours.

Restoring Broken Corners

1. Mix a batch of concrete using 50% Portland cement and 50% sand. Blend in a wheelbarrow with a shovel and mix with water from a garden hose. The concrete should be a workable consistency. This means not too dry and not too wet.

2. Cut back the area of broken concrete until you reach a portion that is in good condition. Construct a concrete form from wood. Measure the width and height and measure boards to place along the length and width of the stair(s) needing a section replaced. Prop them up using cinder blocks, or items that are equally heavy and stable. Coat the boards with motor oil to keep the concrete from sticking to them.

3. Pour concrete into the mold and allow the mixture to start setting up. An hour or two will be a sufficient amount of time.

4. Round the edges of the new concrete to match the rest of the stair. Use a trowel and a putty knife for this. Pull the two boards that make up the mold and smooth the concrete using a trowel. Allow the stairs 2 days to cure before allowing foot traffic.

Tips & Warnings

• Consider using a concrete patching additive to the concrete mix. This will help bond the new concrete with the old. Tim Carter, home improvement specialist with Askthebuilder.com, offers some great tips regarding the use of concrete patching additives.

• Protect the eyes and skin from concrete chemical burn by wearing safety glasses and gloves.

References

• Concrete step repair
• Concrete spalling repair

Resources

• Epoxy patching additives