How to Apply Stone Veneer to an Exterior Basement

Scrub the exterior walls of your basement with a scrub brush and a mixture of water and mild detergent. This can help remove debris that might reduce adhesion of veneer stones. Rise, then allow the walls to dry completely.

Place a carpenter's level on the wall to determine the level line for your stones. Mark the level line at 6-inch intervals from the bottom to the top of the wall, and use these lines to make sure your stones are level as you install them.

Mix enough mortar to attach about 10 square feet of stone veneer. Because mortar mix can dry quickly, mixing too much mortar at a time can contribute to material waste and increase your project costs.

Apply mortar to one corner of the basement's exterior wall with a trowel. Set one veneer stone on the mortar at the corner. Place a section of 2-by-4 lumber on the stone and lightly tap it with a rubber mallet to set it into place.

Continue mixing mortar and installing stones on the exterior wall, leaving about 1/4 inch between each stone for grouting. Vary the sizes of the stones to prevent long, uninterrupted grout lines and give the wall a more natural stone construction appearance. Cut stones as necessary with a masonry saw and a diamond or carbide blade to accommodate windows, utility boxes and other obstacles.

Allow the mortar to dry for 12 to 24 hours. Apply grout between the stones with a grout float, working in small sections and wiping away excess grout or grout that has smeared on the face of the stones with a damp sponge as it begins to dry.

After the grout completely dries, apply a coat of sealant on the finished stone veneer with a paintbrush. Let the sealant dry for 30 to 60 minutes and apply a second coat.