Foundation walls are made from either concrete blocks or solid concrete, with both being a pale gray in color and having a rigid finish. If you are not satisfied with your foundation wall, or if you just want to change the design of your foundation wall, then you can cover it with stick-on stone. The stones require no additional foundation and they can be installed by the average do-it-yourself homeowner in two to three days, depending on the size of the project.
Prepare the foundation wall for the stick-on stones. The foundation wall must be cleaned using muriatic acid. The acid will etch the surface of the foundation and clean away any debris that may impede the bonding of the stone to the concrete. If your foundation has been painted, remove the paint using a pressure washer, and then scrub the wall with a brush and muriatic acid.
Mix type S mortar, brick sand and water to form the mortar mix that will bond the stones to the foundation. Use half a bag of mortar mix, eight shovels of sand, and three gallons of water together using a hoe. Place all of the ingredients into a wheel barrow and stir until you have toothpaste consistency. You want the mixture to be a little sticky rather than sandy. More sand in the mix will prevent the stones from adhering to the concrete foundation.
Place mortar on the back side of each stone using a mason’s trowel. The stones will be flat and will come in various sizes. You can purchase natural or man-made stones; either will do. Once you have coated the back side of the stone with mortar, place the stone onto the foundation wall and press firmly. Begin at the bottom of the wall and work your way up. The stones will go together like a puzzle. Just pick various shapes of stone and stick them where they fit, keeping the spaces—also called joints—between the stones no more than half an inch wide. Allow the stones to set for 24 hours.
Use a grout bag or pointing trowel to fill the joints with mortar. The type S mortar for this application needs to be a bit sandy. So add a half bag of mortar, 10 shovels of sand and three gallons of water to a wheel barrow and mix thoroughly with a hoe. If you are using a grout bag, fill the bag and squeeze the mortar into the joints. If you are using a pointing trowel, take a small amount of mortar onto your mason’s trowel, hold the trowel against the stone joints and push the mortar into the joints with the trowel. After the mortar has set in the joints for 30 minutes, use a wire brush to clean off the excess mortar around the joint. Sweep the stones with a soft-bristled brush, and after 24 hours clean the stones with washing powders and a stiff-bristled brush.