How To Install Cultured Stone












Preparing the Work Area
  • 1
Estimate the amount of stone and mortar you will need using this formula:
Wall area = length x height of the wall
Window area = window length x window height
Wall area covered by corners = linear feet of wall corner x .75
Square footage required = wall area – window area – wall area covered by corners
  • 2
    Apply a weather resistant barrier, or WRB, to the wooden exterior of the wall. Note: WRB is not usually required over cement or masonry.
  • 3
    Staple sheets of galvanized, expanded metal lath over the top of the WRB.
  • 4
    Spread a good mixture of cultured stone–different sizes, shapes, textures and colors–around the work area, so you have many options during installation.
  • 5
    Mix a batch of Type N mortar in a mortar tray or a wheelbarrow. The mortar must be firm and moist before it is ready for use. Stir in a mortar colorant if desired to enhance the look of the cultured stone.
  • 6
    Use a mason’s trowel to spread mortar onto the wall surface, 1/2-inch to 3/4- inch thick. Do not spread any more mortar than you can cover with stones before the mortar sets up and becomes unusable.
       Apply the Cultured Stone
  • 7
    Begin applying the cultured stones from the top down; this avoids getting wet mortar on stones below the work area.
  • 8
    Install the stones so the joints are as narrow as possible–no larger than 1/2-inch-wide–to create a natural effect. Press the stones firmly enough into the mortar to push some of the mortar out from behind the stones. Applying pressure to the stones also will ensure a good bond with the mortar.
  • 9
    Apply the corner pieces first, alternating the long and short legs over the work area. Then apply flat pieces and work toward the center of the work area. Focus on keeping the joints consistent.
  • 10
    Cut, trim and shape stones to fit with wide mouth nippers, a masonry hatchet or a wet tile saw. Use small pieces to fill in gaps between larger ones. Use a dust mask and safety glasses when cutting cultured stones.
  • 11
    When the mortar has become “thumb-print dry,” mix the grout so it is thin enough to be pushed through a grout bag but thick enough to stay in place in the joints. Apply the grout in the joints, then run a metal jointing tool over them to smooth out the joints, remove excess grout and make the installation look as professionally finished as possible. Drying times will vary.