A concrete overlay is a polymer-modified, cement-based topping applied in a thin layer, often 1/8 inch to 3/4 inch, over an existing slab to resurface a worn or damaged floor and create a new decorative finish.
Understanding Concrete Overlays in Decorative Concrete
A concrete overlay is a polymer-modified, cement-based topping applied in a thin layer, often ranging from 1/8 inch to 3/4 inch, over an existing slab. Contractors use overlays to resurface worn, stained, or damaged concrete and to create a new decorative finish without removing the original slab.
What Affects How Well an Overlay Bonds?
Surface preparation is the single biggest factor in whether an overlay lasts. The existing slab needs to be mechanically profiled, usually by grinding or shot blasting, to open the surface enough for the overlay to mechanically key in. Any oil, sealer, or contamination left on the old slab will cause the overlay to delaminate, sometimes within months.
Concrete Overlay vs. Concrete Sealer
A concrete sealer is a thin, penetrating or film-forming product that protects the existing surface without changing its texture or fixing damage. An overlay is a structural resurfacing layer that can fill cracks, restore a worn texture, and completely change the look of the floor, and it is often sealed itself once it cures.
Practical Tips for a Long-Lasting Overlay
Profile the substrate aggressively and clean it thoroughly, since a weak bond is the number one cause of overlay failure. Control joints in the original slab should be honored in the overlay, or cracks will telegraph through. Follow the manufacturer’s cure time before opening the floor to traffic, since an overlay that is loaded too early can crack or scuff before it reaches full strength.
Also Called
Microtopping, resurfacer, concrete resurfacing
