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Installation for Manufactured Stone Veneer

  1. If you’ll be installing the stone product on an exterior project, current building code requires a moisture barrier such as 2 layers of tar paper or two-ply 60 minute grade D paper be applied directly to the building’s surface. Be sure to lay the tar paper from the bottom up so that the top sheets overlap the bottom. Overlap 2 inches on the horizontal seams and 6 inches on the vertical seams. Check your local building code for other specific moisture barrier requirements in your area.
  2. Directly over the tar paper, or directly over the sheeting on an interior project, cover the area with wire lath. A 3.4 diamond wire lath is recommended.
  3. Hang the lath horizontally.
  4. Overlap the lath at least 6 inches on the vertical seams, and at least 2 inches on the horizontal seams.
  5. The lath should feel rough as you run your hand up over it, and smooth as you run your hand down over it.
  6. Use a hammer and 1 3/4″ roofing nails, or an air stapler to fasten the lath to the studs every 6 inches. Then use an air stapler or a hammer tacker to fasten any loose areas or bulges between the studs. A shorter length staple is okay for use between studs.
  7. Cut the lath using a tin snips.
  8. When working with corners, fold the lath tightly around the corner, and overlap a new piece on the other side as you would anywhere else. This rule applies for inside corners also; fold the lath at a 90 degree angle and fit it tightly into the corner, overlapping the lath on each side.
  9. Never have a seam on a corner.
  10. It is very important to nail the lath on both faces of the corner.
  11. You will need to mix three separate batches of cement, one for the scratch coat, one for the mortar, and one for the grout. Each requires a specific ratio of sand, and either portland or masons cement.
    1. Scratch Coat – 1 part Portland cement to 2 1/2 parts sand
    2. Mortar – 1 part Portland cement to 2 parts sand
    3. Grout – 1 part Mason’s cement to 2 parts sand
    4. Note: An alternative cement for interior work only is to use “Type M” cement for the scratch coat, mortar, and the grout. The ratios of cement to sand remain the same. Pre-mixed mortar is okay too.
  12. Dry mix the sand and cement together with a hoe in a wheelbarrow or mud box. This will avoid creating clumps in the mixture.
  13. Slowly add water to the mixture a little at a time and continue to mix. You can always add more water later, but if you add too much, the mixture will become runny and unusable.
  14. Continue mixing the cement adding small amounts of water as needed until it has the consistency of paste.
  15. Use a masonry trowel to spread an even layer of cement over the wire lath. Cover the entire area of lath with the cement mixture. Work the cement into the holes of the lath, and scrape off the excess.
  16. While the cement is still slightly wet, use a soft bristled brush to rough up the scratch coat a little. This will give the stone a better surface to grab to. Virtually no cement should be removed with the brushing process.
  17. Let the scratch coat dry before going on to the next step. Drying time will depend on temperature, humidity and airflow, and could take anywhere from 2 to 24 hours. You’ll know its dry when it turns a light gray color.
  18. Mix a batch of mortar, using 1 part portland cement and 2 parts sand.
  19. Before you apply any of the stone, lay out a couple of boxes in front of your project. This will give you a sense for the variety of shapes and colors you’ll be working with. Arrange the pieces so they fit and look nice next to each other, and try to avoid clumping colors together all in one area.
  20. Start at the corners and work toward the center of the wall. Be sure to alternate long and short returns on corner pieces.