How to Use a Concrete Bonding Adhesive

If you have cracks or splits in a cement slab or on concrete steps, you use concrete bonding adhesive to help cover them and repair the damage. Concrete bonding adhesive allows you to add or pour new cement onto an existing piece of concrete without having to first rough up the surface of the concrete. Without the adhesive, repairing concrete involves a lot more work. Using concrete bonding adhesive is not that difficult and this how-to guide will show you everything you need to know.

(Note - This process is for performing what is known as a 'paint-on' application of concrete bonding adhesive. In most cases, this type of application will result in a bond strength of about 450 psi. If you need industrial strength repair, you can perform a 'Slurry Coat application by mixing the concrete bonding adhesive with Portland cement. A Slurry Coat application will result in a bond strength of 1300 psi, but takes about 3 weeks to full cure and dry.)

Step 1 - Prepare the Surface

Remove any loose concrete rocks or stones from the surface area where you will be applying the concrete bonding adhesive. Also, make sure that the surface is relatively clean from dirt and debris. Use a broom to sweep the surface before applying the adhesive.

Step 2 - Prepare the Adhesive

Shake the container of concrete bonding adhesive vigorously for a couple of minutes before opening it. Then, pour a portion of the concrete bonding adhesive into a separate container and dilute with clean water. Mix 1 part concrete binding adhesive with 2 parts clean water. The first application of concrete binding adhesive will serve as a primer for the final coat.

Step 3 - Prime the Damaged Concrete Surface

Take the paintbrush and apply the watered-down concrete bonding adhesive directly to the damaged concrete area where you will be applying new cement. Allow the primer coat of the concrete bonding adhesive to dry for a couple of hours before continuing.

Step 3 - Apply the Concrete Bonding Adhesive

Once the initial primer coat of adhesive has dried a bit, you can begin applying the final coat of concrete bonding adhesive. Use the paintbrush to apply the bonding adhesive (this time full strength) directly to the damaged concrete surface. When brushing on the concrete binding adhesive, apply a thick coat of adhesive for the best results. Refer to the instructions on the container and wait for the prescribed drying time before continuing.

Step 4 - Mix and Apply New Cement

As soon as the concrete bonding adhesive is dry, follow the directions on the bag of cement for mixing the concrete and apply it to the top of the surface where the concrete bonding adhesive has been used. If you'll be applying a gypsum or finish plaster (instead of cement) on top of the concrete bonding adhesive, you should apply it while the adhesive is still tacky and not yet dry. Otherwise, apply regular concrete once the adhesive has dried.