How to Install Hydrated Lime & Artificial Stone

Preparing the Surface

• 1

  Apply asphalt-saturated underlayment on the wall with 3-inch overlaps. Begin at the bottom of the wall and work to the top. Secure the material with nails spaced 9 inches apart. The underlayment covered by metal lath and a layer of mortar is necessary to protect the wall from rotting as a result of water seeping through from the mortar.

• 2

  Cover the wall with metal lath, commonly called wire lath. Begin at the bottom and work to the top. Overlap strips 2 inches horizontally and 6 inches vertically. Stagger the vertical butt joints as you would brick joints. Drive nails 6 inches apart, making sure there are nails in all studs. Use tin snips to cut the lath as necessary.

• 3

  Mix mortar in the ratio of 1 part cement, 2 parts lime, 9 parts sand and enough water to make the mortar thick enough to adhere to the metal lath. This mortar, called Type O, has a compressive strength of 350 pounds per square inch, sufficient for interior or exterior walls that do not bear loads. Apply a 1/2- to 3/4-inch layer of mortar on the metal lath and let dry for 48 hours. This is called the scratch coat.

Laying the Stones

• 4

  Trim the artificial stones with your saw so that the joints between them will not be more than 3/4 inch wide when you set them into place.

• 5

  Butter the backs of the stones liberally with Type O mortar and apply them to the scratch coat. Put each stone in place and wiggle it to help settle it. Use enough mortar so that it squeezes out around the edges of the stones. If the stones slip, you may be using too little or too much mortar, or your mortar may be too thin. Use a mason’s level to make sure courses of stones are level as you lay them.

• 6

  Wait an hour. Push the mortar that you squeezed out back into the joints. Strike the joints with a metal striking tool when the mortar is set. Brush the joints lightly with a whisk broom so they have a finish appropriate for stones.