A concrete substrate should be checked to see where the damage has occurred. There are several methods of fixing cracks in concrete before applying a decorative overlay.

The cracks can only be filled which is also called bridging. The method requires filling or covering the crack with a stiff material so it remains slightly higher in elevation than its surrounding.

A slight preparation is required.

When dealing with concrete surface science or concrete surfology, we come into what is called a concrete overlay or concrete substrate and repair material. When repairing, the adhesion between the overlay and the concrete substrate is an important factor that decides the durability of the repair. Achieving the maximum strength possible is what everyone should aim for.

When considering the bond material its adhesion strength is an important factor. Compatibility of the materials or their ability to stick together is what we should look for. A successful concrete repair will leave no cracks and will bring your flooring to its former appearance.

When performing a repair, first we need to loosen any concrete and straighten out the crack as much as possible. This can be done using a crack-chaser diamond blade.

The bonding material to be used to cover the crack should tenaciously stick to the concrete surface so that it gradually goes down to the surface level. The overlay and the crack filler will also need to bond well for which a rough profile is required.

We have below three common methods for bridging gaps before applying a decorative overlay are:

Crack Suppression Mats – These mats find successful use in the tile industry and they have been used for several years now. To get to our point, we need to roll out the mat such that it covers the crack by 5 inches on either side (for extensive cracking cover the entire surface).  Using a bonding primer or glue, adhere the mat to the surface.

Cement-based system – Using a feathering technique, polymer-modified cement-based repair mortars are mixed onsite and applied with a trowel or putty knife.  To avoid shrinkage cracking, several thin applications are usually required. As is usually done, to achieve a good bonding surface for the overlay, scratch the surface with a broom or trowel as it begins to set.

Rigid Epoxy Systems – There are different types of epoxies available of which two-part epoxies in self-mixing cartridges or for mixing onsite is used in this case. Using an injection gun or putty knife to fill the crack to overflowing, apply them. On either side of the crack, between 2 to 5 inches, you need to feather out the epoxy. The epoxy is still wet. Use a mesh tape into the wet epoxy to provide additional reinforcement. While the epoxy is setting, cast some course sand onto it to provide a rough bonding surface for the overlay.

If looking to cover seams when applying decorative overlays over wood and other non-concrete surfaces, this crack suppression method can be applied to great effect.