Decorative concrete allows you to transform a plain and ordinary looking gray slab into a surface that perfectly mimics stone, wood, or other more expensive materials. But some of the techniques used for decorating concrete can also effect the longevity and durability of the surface. Antiquing in particular is one common technique that has been linked to cracking and spalling of a concrete surface, but it is perfectly safe to use when applied correctly.

How Is Antiquing Applied?

It's the very nature of the products used to antique concrete that can cause it to delaminate the concrete's surface. Antiquing is achieved by adding a darker color as an accent, and the installers apply this color in the form of a mold release on the stamps and other tools they use to texture the slab. Since the antique release is required both for adding color and to keep the molds and stamps from sticking, it must be a powder or liquid that bonds tightly to the concrete without sticking to the decorative tools.

Why Does Antique Release Cause Surface Issues?

A little antique release here and there offers a natural aged look and doesn't interfere with the bond between sealant and the concrete's surface. If too much of the powder or liquid is left on the surface when sealer is applied, the non-bonding nature of the release agent prevents the sealant from attaching itself to the concrete. It's very easy to leave too much antique release behind even if you're experienced in decorative concrete techniques. Most homeowners don't know what to look for before signing off on concrete work, so they may not notice there's too much of the dark antique color either.

How Can Installers Avoid These Problems?

Taking care to brush or wash away some of the antique release before sealing the concrete results in a strong sealant bond and a better looking finish. The darkest accent color should only cover around 10% of the total surface, with some designs calling for up to 30% of the surface being colored by antique release. Inspect the concrete after it's colored but before it's sealed and ask the installers to clean away more of the release if it looks like it's coating more than that percentage.

What Techniques Will Fix Chipping Surfaces?

Even if your decorative concrete is already chipping and spalling due to an excessive amount of antique release, you can salvage the surface with the right treatment. All of the existing sealer must be stripped away with the right chemicals, then the surface should be ground down and cleaned of excessive antique release. Resealing the surface with less of the release material interfering with the bond will result in more durable decorative concrete.