Bella Vernici's sprayable overlay compound is the crown jewel of the company's stainable concrete veneer system.
The overlay powder is a unique combination of marble flour, lime, fly ash, Portland cements and ultrafine aggregates. At the job site, it's mixed with Bella Vernici's liquid Enforcer, an acrylic polymer, instead of water.
The overlay can be diluted to be as thin as needed and still take stain. It can be applied with a sprayer or rolled or troweled on. More Enforcer can be added without risk to re-emulsify the compound as it starts to set. Emulsions in the Enforcer improve the overlay's flexibility, adhesion and hardness.
“Our overlay has powder-fine aggregates that allow for a smooth finish less than 1⁄16 inch thick in a single pass,” says Bella Vernici Studios art director Rodney Ray. “Additionally, it is sandable for 24 hours to reclaim profiles and eliminate trowel lines. It also can be kept workable for hours on end with additional Enforcer. It can be mixed as thin as soup and sprayed without losing stainability, adhesion or strength.”
Contractors can't get this kind of performance from overlayments that, for binders, use powdered acrylics that emulsify with the addition of water, Ray says. As more water is added to increase workability, the binder becomes diluted and the coating is set up to fail. “Our binder is the Enforcer liquid,” Ray says. “So, the more you mix in, the better. You just want to insure it's blended well.”
The compound works with all stains. However, its alkalinity is very high, so stains that are high in acid content tend to become very intense when reacting to the Bella Vernici overlay.
This problem can be avoided altogether by using Bella Vernici's own Oxidizers to stain its overlay. The Oxidizers are made from metallic salts and have little or no acid in them.
The stains can be applied just one day after the overlay compound. Finally, a hardener topping seals the surface and sets the color.
The sprayable overlay is sold on its own. But the other three key components of the system — the bonding primer, Enforcer liquid and the hardener-sealer — are engineered to work with it. Is the company's bonding primer required before the overlay? “Yes and no,” Ray says. “Yes to the consumer as it offers additional insurance. However, there are instances where enough ‘tooth' is present so as not to require it.”
Bella Vernici Architectural Concrete