Manufactured stone veneer can be used to greatly enhance the look and feel of a project. These hand crafted thin veneer stones are cast from natural stone in a process that captures the natural elegance and beauty of genuine stone. In this article we will be discussing some basic step-by-step installation procedures that can help with your next stone veneer project.
Determining Type of Substrate: There are several types of substrates that manufactured stone veneer can be applied to if the surface is properly prepared. The most commonly used are plywood, cement board and CMU. Varies substrates require different preparation processes. It is important to use the right preparation techniques and tools for each project. (Note: Review the stone manufacturers detailed installation instructions before installation any project)
Applying Weather Resistant Barrier: It is recommended that you install two separate layers of WRB in shingle fashion, starting at the bottom of the wall. The upper layers of WRB should overlap the top of the lower layers by a minimum of two inches. The WRB should be installed in accordance with the manufacturer’s recommendations. (Note: This step may not be required for some installations. Please review your stone manufacturers detailed installation instructions.) Recommended Material: #15 felt or Grade D paper
Applying Galvanized Metal Lath: Lath should be installed horizontally with the cups up, and should overlap a minimum of one inch on the horizontal and vertical seams. Around inside and outside corners, lath should be attached every six inches allowing a 16 inch overlap around corners. Recommended Material: 2.5 lb. or 3.4 lb. self-furring corrosion resistant lath
Applying Scratch Coat: Apply a nominal ½” thick layer of mortar over the lath, ensure the lath is completely covered with mortar to allow for scoring of the surface. The mortar should be applied with sufficient pressure and thickness to fully embed the lath. Once the mortar is thumb-print hard, scratch the surface horizontally with a notched trowel or scarifier to create a scratch coat. Recommended Tools: Notched trowel or scarifier
Snapping Chalk Lines: After the scratch coat dries (usually 48 hours) and before the stone is applied, chalk lines are snapped across the wall for the purpose of proper horizontal alignment of stone. The chalk lines are necessary in keeping the courses of stone straight and level during installation, which provides for a beautiful and professional result. Recommended Tools: Chalk Line
Mortar Coverage (Back of Stone): Cover the entire back of the stone with approximately ½” of mortar. This will ensure a proper adhesion between the stone and the scratch coated wall surface. Please follow the manufactures recommendations regarding mortar mixture formulas. (Note: Weather conditions can affect the adhesion of mortar to the scratch coat. Please review the stone manufacturers detailed installation instructions for different weather environments.) Recommended Material: Polymer modified Type-S mortar / Recommended Tools: Trowel
Installing the First Course: When installing the first course, start at the bottom corner of a wall installing one or two corner stones first. Corner pieces have a long and a short return, these returns should alternate in opposite directions on the wall’s corner staying within the 8″ chalk lines. Continue the project by installing flats off of these corner pieces. Work the stones into the wall with a side to side motion to create a bond. Each additional course that is installed will always begin with a cornerstone.
Cutting Stones to Fit: Manufactured stone veneer is easily shaped or cut as desired. This enables you to fit stones quickly into place, insuring a natural looking wall with tight mortar joints. (Note: Always wear safety glasses while cutting stone veneer.) Recommended Tools: Makita 4.5″ handheld disc grinder with diamond blade, or nippers.
Grouting the joints: If grouting is required, use a grout bag to fill in the joints. Try to avoid smearing grout on the face of the stone. If grout does come in contact with the face of the stone, use a clean damp sponge to remove the residue.(note: make sure sponge is clean to avoid smearing grout elsewhere) Once the grout is thumb print hard, use a metal joint tool or wood stick to finish joints. Use a whisk broom to sweep away any left over debris. Recommended Tools: Metal joint tool or wood stick
Grout Color and Style: The color of the grout joint has a dramatic impact on the final appearance of the installation. From varying depth raked joints to full brushed joints, there are several grouting techniques that also impact the final appearance.