How to Lay Stone on Existing Walls
- 1). Choose a stone, real or manufactured, and a style patterned in regular squares or rectangles of varying sizes and shapes. Measure the wall to determine the square footage and buy enough stone to cover it plus about 10 percent for errors and breakage. Decide on a fixed pattern if you're using regular shapes. This can be overlapping bonds like stacked brickwork with all widths the same or in varying widths in different courses.
- 2). Prepare the wall. Remove any covering on a wooden wall down to the sheathing. Clean dirt or debris from a masonry wall, whether concrete block or poured concrete. Eliminate bumps or other irregularities in the surface and patch any cracks or breaks. Install metal lath on a wood wall, nailing tightly to the face with a hammer and lath nails.
- 3). Cover metal lath with a thin layer of mortar spread with a mason's trowel and let it dry overnight. Moisten the dried mortar or the concrete surface with a garden hose misting nozzle. Set a string line between two stakes and level it with a line level as a guide for installing stone facing. Lay regular patterned stones in level courses; natural stone courses will vary in size, but use the string as a guide to keep them fairly equal up the wall.
- 4). Install the first stones at a bottom corner, flush with the end of the wall. Spread a thin layer of mortar on the wall and mortar the bottom and back of a stone. Press it firmly into place until it holds. Add other stones, working across and up the wall in a triangular pattern. Lay stones along the base, then up the wall. Work in small sections, mixing only enough mortar for about 30 minutes at a time.
- 5). Face the entire wall with stone. Cut stones with a masonry saw (or mason's hammer and chisel), if necessary, to make the last course level at the top. Go back over the wall and remove any excess mortar from the stone faces. Use a damp cloth or wet brush. Let the mortar set overnight, then go back and remove any remaining excess mortar with a wire brush.
- 6). Put grout in seams, if desired, with a grout bag, which is a fabric bag with a pointed metal tip. Squeeze grout through the tip into the joints until they are filled. Smooth grout with a mason's finishing tool, a metal device with a rounded tip that will form grout into a concave shape.
