A concrete overlay covers worn or damaged concrete surfaces
A concrete overlay often replaces a worn or damaged concrete surface without the expense of replacing the entire slab. Once placed, the overlay provides a new surface that can be finished as you would any other poured slab, coloring or stamping it as desired. Placing an overlay has its difficulties though. The new surface must bind with the old without causing stress cracks to develop in the overlay or moisture to collect between the two surfaces. It is possible to avoid these problems such that your strong, durable overlay extends the lifespan of your concrete slab.
Instructions
1. Clean the surface of the concrete using a power washer to remove any dirt or debris. Use a pH-neutral cleanser to wash the slab. Clean any oil from the slab using a commercial degreaser. Rinse cleaner residue from the concrete with clean water. Allow the slab to dry overnight before proceeding with the overlay.
2. Repair any cracks in the concrete surface. Put on a pair of safety goggles, work gloves, face mask and a respirator to repair the surface of the floor. Fill the cracks with joint repair compound, pushing the compound into the cracks with a putty knife. Scrape the compound at the top to level it with the surface. Wait for the compound to dry, according to the manufacturer's suggested drying times.
3. Texture the concrete slab's surface using a concrete grinder so that the overlay will bind better. Run the grinder over the surface of the concrete to roughen the surface with a series of scratches. You can rent a concrete grinder at a home improvement store or an equipment rental shop. Sweep up any dust left from the grinding process.
4. Apply a layer of bonding adhesive onto the surface of the tab, using a squeegee to spread a thin layer of the glue. The layer of adhesive will bind to the new overlay, preventing the old slab and the overlay from moving separately and causing cracks. The adhesive also prevents moisture from gathering between the two surfaces and causing damage. Allow the adhesive to dry until the surface is no longer wet, but remains sticky to the touch.
5. Mix the overlay following the manufacturer's instructions in a large bucket or wheelbarrow. Add concrete colorant, if desired, during the mixing process. Pour the overlay onto the adhesive using a spade to spread out the material evenly. Make sure to fill any holes in the concrete with the overlay material. Level the overlay using a steel trowel, and then go over the new surface with a wood float to settle the aggregate in the mixture and pull water from the overlay to the top to aid in curing. Allow the overlay to cure for the time recommended by the manufacturer.
6. Finish the overlay, applying any concrete stain, or stamping it as desired.
