How to polish self-leveling concrete overlays?
Many commercial and residential properties are installing polished self-leveling concrete overlays to enhance their appearance. This type of concrete overlay is a simple solution for adding a beautiful finish that is easy to maintain.
Not every existing concrete slab is the ideal candidate for basic polishing. Any slab that shows existing carpet tack holes or experiences major flaws can be patched. However, every repair will show through the polish. As an alternative, many architects, contractors and residential homeowners are turning to polish-able concrete overlays as a solution. The product not only hides any existing flaw in the concrete substrate, but adds significant versatility and architectural design.
In some applications, the concrete overlay is applied because of its self-leveling properties. It works as the ideal solution for evening out a flaw or unleveled existing substrate floor. Through a simple process of preparing the substrate and applying the new self-leveling materials, the floor is leveled and ready for polishing. Additionally, the overlay can be applied using surface aggregates including glass to produce a unique and aesthetically pleasing design.
Polishing the Floor
To get professional results on the newly installed concrete overlays, it is imperative to polish the floor with a planetary grinder. The process of polishing should begin within 24 hours after the overlay has been placed. Diamond tooling with a metal bond is ideal to achieve the proper results. The initial grinding should begin with 80 grit, with the honing stage at 100 grit.
If the concrete overlay was seated with some type of glass aggregate or other material, it needs to be ground down enough to remove any air voids. The process also includes keeping the equipment steady during the grinding process, especially during a pull back of the machine. Grinding concrete overlays typically requires using the machine at a higher RPM than is the standard.
Application of the Densifier
For a proper result in a high quality polished concrete overlay, it is important to add a colloidal densifier that is silicon-based. The fine particle size of the product will produce optimal results when compared to traditional potassium-based or sodium-based densifiers. Because of the porosity of concrete overlays, it is essential to add double the spread rate of densifier to achieve optimal results.
The final stage of polishing includes using diamond-impregnated pads. As a recommendation, 200, 800 and finally 3000 grit are ideal, with the RPM set as high as possible on the machine. Just before burnishing, it is important to apply a high quality professional grade floor conditioner that will enhance the shine and protect the floor.