Prep the Materials and Layout
To get started, I picked up the mortar to set the tile. I’m using a bag of mortar made for use with natural stone tiles. Sometimes you can get away with an easy-to use pre-mixed options sold as modified thinset, mastic, or tile adhesive. While these are somewhat easier to use, the chemicals in the mix can leach into natural stone tiles and darken their appearance, so it’s best to use a mortar that mixes with water and then expels that water as it cures. Next I picked up a bag of grout marked “non-sanded” to be sure I don’t scratch the finish on my tile as I wipe it clean. With my supplies home, I was ready to check the layout of my tile.
For the hearth, I laid the individual tiles front to back on my hearth, inserting 1/8-inch spacers between the tiles, to figure out the number of rows. And then laid them side-by-side at the widest part to get an idea of how many tiles would fit in each row. Because this was a smaller project, I decided to layout all my tiles and took some time to stagger the darker tiles and remove any blemished tiles. I then stacked them up in rows to the side of the hearth. For the surround, I went a bit overboard and cut a cardboard template so I could lay it flat and get a rough layout of my mosaic sheets. This can also be done on the floor with painter’s tape, and helped me get a visual of the design. After a quick final cleaning of my substrates, I marked the centerline on the hearth, and got ready to mix my mortar.
Mix the Mortar
Because I was renting a tile saw, and only wanted to rent it for one day, I decided to install the majority of the hearth tile first so it could set overnight. That way I could spend the time on the tile saw rental day getting the surround pieces cut and installed, and then quickly cut the edge tiles for the hearth. Also, by doing it in this order, the hearth tile was completely set on the second day (i.e. I didn’t have to worry about disturbing the tiles), which is typically why you would want to start with the surround and work your way down.
For the small hearth, I only wanted to mix a half bag of my mortar so I called the manufacturer to get the ratio, which was three parts mortar to one-part water. So I poured one container of water into the bucket, and then three containers of mortar. Using a paddle mixer fitted into my drill, I slowly mixed the mortar to a peanut butter consistency, let it rest for 10 minutes and then mixed it again. I then placed the paddle mixer into a bucket of clean water and ran it for a rinse to remove all the mortar.
Spread and Comb the Mortar
Starting to one side of the centerline, I smoothed the mortar onto the hearth with the flat edge of the v-notched trowel, and then used the notched side of the trowel to comb ridges into the mortar.
Lay the Hearth Tile
I positioned the first tile in place to the right of the centerline and then gave it a nudge front to back to set it into the ridges. I then continued placing the rest of the tiles in the row, using the spacers. When I got to the second row, I offset my first tile by half the width of a tile to create a brick pattern. Remember this “half width” also accounts for the width of the 1/8-inch-wide joint. I continued placing each row until I reached the edge where a tile needed to be cut, working my way to the left side and then to the front edge of the hearth.
Cut the Tiles
That night I rented the saw for 24 hours. It’s a pretty big saw that requires two people to lift, so I got it set up that night while I had help, and then was ready to go first thing in the morning.
I’m using the medium tile saw from Home Depot Rentals—It has a sliding deck on it that holds 12″x12″ tile. Since I’m cutting a 12″x12″ sheets of mosaic tile, this will make it easy for the whole sheet to lay on the deck and cut really smooth. The deck slides and the blade stays still. Once you fill up the reservoir with water, there’s a pump in the back that feeds water down over the blade.
As a last bit of prep, I also covered the firebox and hearth with plastic secured with painter’s tape to guard against any falling mortar while I worked on the surround the next day.
Lay the First Surround Tile Sheets
To tile the surround, I started in an upper corner so I could force a nice looking alignment on both the leg and the top section. To do this I squared off the top edge and then the side edge of a sheet and cut along the inside corner that fell over the firebox.
To install the tile, I mixed the mortar in the same way as the day before, and then applied it to the surround with the smooth edge of the trowel. I combed in horizontal ridges, and then pressed the tile sheet in place. With my alignment set, I could now trim the right leg pieces to width, accounting for some joint spacing along the outside edges of each sheet.
TIP: Through some trial and error, I found that my mosaic tiles were falling into the valley of the tile saw’s deck, so I placed a board under the tile, adjusted the blade higher (so it just touched the board) and then cut the sheets to size.
Again I combed the mortar onto the surround, and then pressed the sheets into place. When I got to the bottom of the leg, I measured and cut the bottom edge square, and then installed the sheet. Next I moved to cutting and installing the top strip of the surround, applying and combing the mortar, and then pressing the tiles into place, paying special attention to closing the gap between the sheets. I then worked my way down the left leg, measured for the last sheet, and cut and pressed it into place.
Cut the Hearth Tiles
With the hardest part complete, I was feeling pretty good, and moved on to the straightforward task of trimming the hearth tiles. Most the tiles only needed to be trimmed a bit shorter, but two tiles needed to “wrap” the corner of the mantle, so I made two passes on the saw to create the L-shaped pieces. With my pieces sized, I back-buttered them with mortar, combed a groove, set them into place, and then added spacers.
The tile-cutting part of the process was a success, but definitely took time. I ended up returning the saw right at the end of the day, and then let the tile set undisturbed overnight.
Grout the Tile
The next day I removed the spacers on the hearth and covered it with plastic so I could first grout the surround. I mixed the grout as specified on the packaging with the paddle mixer. Using a grout float, I pressed the grout into joints, and then swept over the area at an angle to remove the excess. I kept a dry rag handy to clean the metal trim around the firebox, and to wipe the inside walls of the mantle. When the surround was fully grouted, I removed the plastic, and wiped all the edges clean. Next I moved to the hearth. Again pressing the grout into the joints on a diagonal, and running the float over the tile to remove the excess. After 20 minutes, I cleaned the tiles with a damp sponge. It’s important to work with a clean bucket of water and fully wring out the sponge so you don’t introduce too much new water to the grout. Again I let the tile and grout set undisturbed overnight, though most grouts say you can clean after just a few hours.
Clean the Tiles
On the last day, I wiped the tiles clean with a microfiber cloth to buff off the haze. I wiped them down one last time with a damp cloth, and then waited a few days before spraying a wiping on a few coats of sealer for extra protection. To finish this part of the process, I replaced the floor trim and reinstall the baseboard molding on the legs of the mantle to complete the look.
With the mantle updated and the new tile installed, I can now work on the built-ins that will set on either side. Check back on Sept 13th, 2019 for that tutorial or watch my Instagram Stories to see my daily progress!