How to Install Manufactured Stone on the Underside
- 1). Put on safety goggles. Verify that your substrate is flat and sound (if cement board) and "cured," or dry, if the substrate is mortar. Knock down any obstructions of mortar. Lay out and organize the pieces of manufactured stone that you will use on the underside of the structure, making sure that you have enough and that they fit together.
- 2). Find the center of the installation area, mark it with a construction pencil and snap a chalk line. This will be your starting point, but remember to "stagger," or offset, the pieces that are going to be installed on the underside of the structure with the areas of the wall that are finished (if applicable).
- 3). Mix acrylic-modified thin-set mortar; this will be your bonding agent, or what will keep the manufactured stone in place for years to come. Mix the thin-set to a stiff consistency. Use a mason's trowel to cover the back of a stone piece, taking care to have a consistent, even bed of thin-set. Do not get any thin-set on the finished surface of the stone.
- 4). Use a ladder (if necessary) to reach the underside area and apply a thin coating of thin-set to the immediate installation area to ensure a good bond. Climb the ladder with the initial piece and press it into place, positioning yourself to be able to apply a reasonable amount of pressure. Some thin-set may be released at this point. That's OK. Continue pressing the piece in place, moving slightly back and forth to make sure that there is an adequate bond. Step back from the ladder and confirm that the piece has not moved or sagged.
- 5). Continue installing the full pieces of manufactured stone on the underside of the structure until you need to start cutting pieces. Use either a chipping hammer (a rougher look) or a 4-inch grinder to cut the necessary pieces. When you are finished with the installation, allow 24 hours for the underside to dry.
- 6). Clean the underside pieces with a sponge and a soft nylon bristle brush. Use clean water in a bucket to rinse the sponge and brush periodically. Take special care to not brush or scrub the surface of the stone excessively, as this may scuff or damage the stone. Allow time for the stone to dry before grouting.
- 7). Mix a matching grout to a medium consistency. Use a mason's trowel to fill a grout bag with it. Test the consistency of the grout in the bag by squeezing the grout through the ''nipple" of the grout bag. Add water if the grout won't pass through the end. Apply the grout to the spaces between the stones and avoid the surface of the stone. Allow the grout to dry before tooling and working it with a pointing trowel and mason's trowel. After 24 hours, apply a masonry or tile sealer to the manufactured stone using a sponge or squirt bottle.