Install building sheathing such as plywood or cement board over the studs. Cover with building paper and wire lath before applying the scratch coat for manufactured stone. The wire supports the mortar used in the scratch coat and reduces cracks and fractures in the mortar during seasonal shifting of the building. Wire lath is not required on solid surfaces, such as brick, concrete block or surfaces that already have wire lath, such as stucco. After completion of the supporting structure, if needed, install the scratch coat for manufactured stone.
Mix mortar according to the package directions in a 5-gallon bucket or a wheelbarrow, depending on the size of the project. Be sure to scrape the sides and bottom of the container to mix all of the mortar powder into the mix thoroughly.
Start from a bottom corner. Spread an even coat of mortar that is approximately ½ to ¾ inch thick on the wall with the flat side of a mason's trowel.
Scratch this coat of mortar with a hand rake or mason's scratcher with horizontal strokes so the surface is not smooth. Allow the scratch coat to dry for at least 48 hours.