Repair cracks in masonry using a vinyl concrete patch that you stain to match the stone or brick. Fix cracks in mortar joints by mixing new mortar to refill the damaged area. Repairing cracks is essential to prevent further weathering of the masonry.
Begin the process by cleaning the crack with a wire brush. Use a hammer and chisel to break away any loose material from the damage. For mortar joints, avoid removing more than one-third of the depth of the joint. Put on eye protection, and use an air hose to blow any dust from the repair area.
Mix stain from the repair kit to match the color of the existing material. Use a pointed trowel, and press the vinyl patch into the crack. Continue adding more material until the patch is level with the surface.
Repair mortar by mixing the mortar mix in a tub or wheelbarrow. Add about half the water the directions recommend at first, and then add small amounts as you mix until you can form a ball that holds its shape with the mortar. Allow the mixture to stand for about an hour, and add more water so it is pliable yet stiff.
Use a garden hose to wet the damaged area. Use a trowel to push the mortar into the repair. Continue pressing more mortar into place, and ensure there are no remaining air pockets. Pack the joint with mortar to reach the face of the stone. Allow it to dry for 30 minutes, and use a mortar rake to drag through the joint.