How-to-Install Tips for Field Stone Exterior Wall Covering

Apply grade "D" waterproof tar paper to the exterior of the home if it is wood. Secure to the home with staples.

Attach expanded metal lath to the exterior of the home if it is wood, painted stucco or painted concrete. If the surface is concrete or stucco that has not been waterproofed or painted, the metal lath is not needed. If using metal lath, overlap vertical edges by 6 inches, and horizontal edges by 2 inches. Never place a seam on one of the house's corners. Use tin snips to cut the metal lath.

Smooth a mixture of sand and cement mortar over the wall, using a trowel. This is called a scratch coat, and should be applied as thin and evenly as possible.

Rough up the surface of the scratch coat with a rake. Allow to dry for 48 hours before proceeding.

Spread a selection of field stones out on the ground before you begin placing them on the wall. Mix up stones from several boxes, so you will have a uniform mix across the entire wall. Use field stones of various sizes and textures beside each other for the most natural look.

Coat the back of each stone with 1/2 to 3/4 inch of mortar. Work with one piece at a time. If the weather is particularly dry or hot when installing field-stone coverings, spray the back of each stone with a water hose before applying the mortar. This keeps the stone from absorbing the moisture from the mortar.

Press the field stone firmly against the exterior, pushing until mortar seeps out from under the stone. Start at the top and work across and down, doing the corners first. Place large stones first, and go back and fill in with smaller stones to create a natural look.

Clean the mortar joints. After the wall has dried at least 30 minutes, use a stick to press the excess mortar into the joints. Then, brush out any excess mortar with a wire brush.