How to Mortar Manufactured Stone

Manufactured stone, also called cultured or architectural stone, adds beauty and value to your home, inside or out. Once installed, manufactured stone looks like natural stone construction. It's lightweight and less expensive than real stone. The stone comes in a variety of textures and colors to mimic brick, stone, and slate.

Things You'll Need

• Rubber gloves
• Trowel
• Scratch-coat rake
• Wheelbarrow
• Hoe
• Hammer or staple gun
• Galvanized staples, masonry screws, or masonry nails
• Grout bag
• Wooden stick or jointing tool
• Type N mortar
• Whiskbroom
• Optional:
• Weather-resistance building paper
• Galvanized woven mesh
• Iron oxide pigments

Instructions

1. Install the stone on any structurally sound wall. Clean the surface to remove dirt, mildew, and any loose particles.

2. For surfaces other than untreated masonry, concrete, and stucco, you must first apply a barrier such as weather-resistant building paper and galvanized wire mesh. Install weather-resistant paper using a staple gun with galvanized staples, or with masonry screws or nails.

3. If you need to install galvanized wire mesh, sections of the mesh must overlap by 2" on the surface and by 16" around corners.

4. Mix mortar for the scratch coat. For 50 pounds of dry mortar, add one gallon of water. Mix thoroughly. The mortar should be firm and moist, cling to the trowel, and release when you shake the trowel. Add small amounts of water until you achieve the correct consistency.

5. Apply scratch coat. Scoop some mortar onto the trowel and spread in even ½ inch to ¾ inch-thick layer. When the mortar begins to firm, drag the scratch-coat trowel across the mortar making approximately ¼-inch grooves. Allow mortar to cure completely, which can take up to 24 hours.

6. Plan your design by arranging stones on the floor in the desired pattern.

7. Moisten the surface of the wall. This creates a stronger bond.

8. Mix the mortar per instructions in Step 4. Add iron oxide pigments if desired.

9. Dampen the back of the stone. Scoop some mortar onto the trowel and smooth onto back of the stone in a ½ inch-thick layer.

10. Press the stone onto the wall so mortar squeezes out from the edges of the stone. While pressing, gently wiggle the stone to ensure a strong bond. Space the stones ½-inch apart.

11. Once all the stones are in place, fill the grout bag with mortar and squeeze mortar into the gap between the stones.

12. When the mortar is firm to the touch, scrape out the excess mortar in the gaps with a stick or jointing tool. Do not scrape too deep or leave a groove in the mortar joint.

13. Brush the stone and joints with the whiskbroom to remove loose dry mortar.

Tips & Warnings

• Wear long pants and a long-sleeved shirt. Apply stones from the top down to keep stones clean. Apply stones to corners and around openings first.

• Keep children away from the work area.

References

• Umaco Inc.
• Lowe's

Resources

• Umaco Inc.
• Owens Corning