Stucco is a material that can be used to cover concrete, brick, or cinderblock and is primarily used for exterior construction. Stucco can be made of aggregate such as cement or sand and is applied to a substrate while it is still wet. Stucco can be sprayed onto a surface to create a solid surface. Once dried, it hardens to a solid material. Modern stucco is often made with acrylic fiber or other synthetic materials. These add strength and weather-proofing capabilities. Stucco is durable and can withstand harsh climates. Spraying new stucco can fix cracks, holes, and other damage to the stucco.

The Old Stucco: A Study

Stucco must only be applied to surfaces that have the potential to form a bond. Existing stucco can be sprayed with new stucco, provided a strong bond can be made. Stucco that has been sprayed or applied to other stucco types will not be held in place by old stucco. Before applying stucco to old stucco, make sure you inspect the stucco for cracks and hollow spots. Visual examination can identify cracks. By tapping the stucco lightly with your hammer, you can find hollow spots.

Repairing and cleaning old stucco

You can fill cracks in old stucco with your hands. Use approved stucco. The old stucco should have any hollows removed and hand-patched. You should scrub all surfaces of old stucco with a stiff toothbrush to remove dirt, contaminants, debris, and any flaking stucco. Clean stucco with a hose or scrub brush. If the stucco is very dirty, you should use a pressure washer before applying stucco. Let the old stucco dry completely.

Surface Prep for Old Stucco

Apply a bonding agent before applying stucco. A bonding agent is a liquid that bonds stucco to the substrate. You can apply the liquid bonding agents by rolling or brushing the old stucco. You should refer to the manufacturer’s specifications. They usually state that the agent can be used once and then re-emulsified.

The bonding agent will reactivate the stucco and bond it with the wet stucco after it dries. The bonding agent must be activated only once it has dried. If the dry time is not sufficient, the agent will have to be reapplied. Refer to the manufacturer’s instructions for specific applications and coverage. Use only the amount that can be used with wet stucco that day. Apply the bonding agents on the day they are applied. Overnight humidity and dew will activate them and make them useless.