DIY Cement Overlay

Cement overlay is the process by which you cover old cement with a thin overlay of new cement. Done right, a cement overlay can save you thousands of dollars in materials and labor. Any do-it-yourselfer with little or no experience can achieve cement overlaying in one to two days, depending on the size and scope of the project.

Things You'll Need

• Pressure washer
• TSP (trisodium phosphate)
• 5-gallon bucket
• Acid brush
• Cement overlay mix
• Squeegee

Instructions

1. Clean your old cement surface with a pressure washer to remove excess dirt and debris. Rent a pressure washer at any tool rental store if you don't have one. Place a low pressure tip on the pressure washing wand to prevent damage to your concrete -- perhaps a green or yellow tip. Wash from side to side, ensuring that all concrete is exposed.

2. Apply degreaser directly to any oil spots, and allow it to set for 10 minutes. Scrub the oil spot with a stiff-bristled brush. Wash off the degreaser with a pressure washer.

3. Add TSP and water to a 5-gallon bucket. Follow the mixing instructions on the TSP box to determine amount of powder and water. Apply the TSP mixture to the entire concrete area and scrub vigorously. Allow the TSP to set for 10 minutes and wash off with a pressure washer. The TSP will loosen the top layer of the concrete, allowing for better adhesion of a new overlay.

4. Mix cement overlay powder, found in 10 lb. bags, into a 5-gallon bucket. Follow the bag directions for amount of water and mixing instructions. Blend the contents with a drill and a mixing bit, which you can find at any hardware store. Pour the overlay directly onto the cleaned concrete from the 5-gallon bucket. Begin in the center of the concrete and work out. Push and pull the overlay with a squeegee. Avoid applying too much pressure on the squeegee. Allow only the weight of the squeegee to press on the concrete surface.

5. Allow the cement overlay to set for 24 hours before you walk or drive on the surface. However, test the surface with your hand before walking on it to ensure that the overlay is fully dry.

Tips & Warnings

• Apply more than one coat of overlay for a thicker cement bed.

References

• "Concrete Solutions"; Michael Grantham, et al.; 2009
• "Structural Renovation in Concrete"; Zongjin Li, et al.; 2009
• "Design Ideas for Decorative Concrete and Stone"; Ellen Frankel, Mervyn Kaufman; 2006