A natural stone veneer can be a great addition to any home. What follows should give you enough information to install one on your chimney.
Step 1 - Preparing the Work Area
To begin, you will need to cover your chimney completely and tightly with roofing felt. Use a staple hammer and as many staples as necessary to make sure that the felt is completely flat against the chimney. Once you have secured your roofing felt firmly in place, you can proceed to cover the area in wire mesh. The best way to do this is by nailing it in place with roofing nails.
Step 2 - Preparing the Mortar
Now that your chimney is set up and ready to receive your veneer, you need to get your mortar ready. Mix the mortar according to the instructions it came with. You will know that it is ready when it has a thick, paste-like consistency.
Step 3 - Applying the Scratch Coat
Get out your trowel and use it to apply mortar to the felt and mesh. The coat of mortar should be roughly 1/2 inch thick. Be sure to push the mortar into the mesh, instead of simply applying it as a layer on top. Once you have done this, allow the mortar to partially dry, and then make scratches into the coat using your trowel. The scratches should be roughly 1/4 to 1/8 inch deep.
Step 4 - Attaching the Veneer
Now that your surface is prepared, you can begin to attach the veneer. Begin by applying a similar coat of mortar to the veneer itself. Spread it evenly at a thickness of about 1/2 inch. Once you have done this, press the veneer against your prepared chimney. Start at the bottom and press down firmly, working your way up. Once the section of veneer is firmly attached, you can go over the edges with your trowel to remove excess putty. At this point, repeat the process for each section of the veneer. Be sure to keep the space between sections as consistent as possible, and clean off the edges as you work.
Step 5 - Attaching the Last Piece
Unfortunately, the last piece of veneer may be difficult to get into place, especially if you have varied the placement or gap widths mistakenly. This is to be expected. Because of this, you should keep a hammer and chisel at hand if you need to work on the final section a bit to make it fit.
Step 6 - Applying the Grout
To finish up, you will need to apply grout to the spaces between the sections of your natural stone veneer. To begin, mix the ingredients of the grout mixture according to the manufacturer's instructions. Next, apply the grout to the spaces between the sections of veneer using the grout bag. At this point, do not worry about using too much grout. Finally, scrape away the excess with your putty knife.
Step 7 - Finishing Up
You should seal the veneer with masonry sealant once it is completed and the grout is dry.