How to Install a Stone Veneer Fireplace: DIY Guide & Tips

Easily the most intimidating part of our living room makeover was figuring out how to install a stone veneer fireplace.

I’m no stonemason, and it took some really mad people on the internet, an all-nighter, a lot of googling, and a lot of self-doubt before we finally got there (i.e. the life cycle of just about every project). There are a few specifics about how to install a stone veneer fireplace that differ to other similar projects (like tiling). So, let’s go over the process of how to install a stone veneer fireplace.

How to install a stone veneer fireplace

It needs a strong backing

We built our entire fireplace from scratch, so we were able to control every element that went into making a solid structure. The inside is built from 2x4s, and I figured out how big I wanted the finished fireplace to be, then I worked backwards subtracting all the layers (cement board, mortar, etc.) to calculate my cuts.

I wrapped the whole fireplace in ½” Hardiebacker (a common brand name for cement board). We’ve used ¼” backer board in past floor tiling projects which is much easier to cut and handle, but after doing some research, learned that in vertical installations (and especially when it’ll be holding a lot of weight like in installing a stone veneer fireplace), the thicker size is required.

I used a mesh tape and thinset to go over all the seams and screw holes and was ready to bring in the stone.

NOTE: There are multiple methods of backing the stone veneer, including adding a metal lath sheeting with a “scratch coat” of mortar, but in using the special mortar we used (more on that below), we eliminated those extra steps. Make sure to research your own type of stone veneer to make sure the standards are the same.

The prep work

Basically, it’s like a giant puzzle but with a bit more freedom. We had about six boxes of stone veneer to work with, so I laid out construction paper over our living room floor and took all the stones out of their boxes to sort them. I made a pile for corners, skinny/filler pieces, then small, medium, and large stones and this made it a lot easier to just grab one I needed while I worked than if I had been searching through one big pile.

Also, whether you’re installing stone veneer or tiling, it’s a good idea to take all the pieces out if you’re working with multiple boxes because sometimes there can be color variations between them and you’d hate to find that out after you’re done.

I measured the dimensions of the fireplace on the wall and transferred it onto the paper I’d laid out to make a template, then spent a couple of hours putting stones in place on that paper making a rough plan for myself. I do think this saved a lot of time in the application stage, though my plans did shift a little when I got everything onto the fireplace and changed my mind.

I also laid some paper and painters tape down all around the fireplace work surface to protect it from any mortar spills. I definitely recommend this, just make sure the tape starts about three inches out from the cement board to account for the stone going over that space.

Stone veneer is kind of like more chill tiling

This might be a “duh” kind of statement, but adding the stones is the most intimidating part of installing a stone veneer fireplace. We used Eldorado Stone in the style Shadow Rock (the color is called Somerset), and I was so impressed with this product.

A note: Eldorado gifted us the stone veneer to use in this project, but we’re genuinely so happy with it! My upper arms were already tired of thinking about lifting heavy stone and I was so pleasantly surprised that each piece was quite light, and the colors are beautiful.

Stone veneer requires a specific type of mortar (polymer modified mortar) so that the pieces don’t sag as they dry because they’re much heavier than a regular tile. Other than that, though, the process is fairly similar to tiling.

I added mortar to the cement board, and to the back of each veneer piece with a trowel (this is called back buttering), notched it out, and added it to the cement board. Some of the pieces had really deep grooves or fit awkwardly and I needed to back-butter only, but it still worked out.

Because stone veneer has such uneven backing (as in, some parts dip in and are thinner than the overall piece), it’s a good idea to stop every few stones and pull it off once you’ve applied it to make sure all your trowel lines have been smooshed. If they haven’t, it means the mortar isn’t adhering to that section of the cement board, so you need to add more in that spot.

It’s going to seem like you’re adding way too much mortar to each piece, but for a good hold you want the mortar to be squishing out of each side of the piece when you push it into the cement board. Being that stone veneer pieces are usually between 2 and 3 inches deep, a bit of mortar spill on the sides won’t be seen in the end result, but you can always use your finger to wipe away any excess that’s sticking out farther than the stone.

On a couple of the corner pieces (that are the heaviest), I found the stone was still slipping after I’d placed it so I put some foam pieces and cardboard from the fireplace insert shipping box into the gaps to hold it in place for about 15 minutes before it was set enough to remove the foam.

How to lay the stone

If you’re doing a hearth, make sure to add those stones first and build around them. It would be much harder to cut around the stone afterward, whereas the hearth pieces are just squares!

For the actual fireplace, make sure to start with the corner pieces and place those all the way up the sides. From there, you can build out the inner stones to fill out the space. The spacing between each piece is really a personal preference, as well as whether to make it look more like rows of stone or more scattered. Because I was going for the European farmhouse vibe, my stones are quite far apart and I angled some of the pieces to almost sideways so they looked a bit more random.

Our stone veneer had variations of reddish, brownish, beigeish, and greyish stone pieces, so I also deliberately tried to alternate those so the end result would look more natural.

We used the specific type of mortar recommended for our stone, which comes in a powder you mix with water. It’s a pretty simple process, but you need to make sure you’ve got a 5 gallon bucket handy, and a paddle mixer attachment for your drill. Also, make sure to add water first before the powder or the powder will all clump at the bottom and be impossible to mix properly!

How to cut stone veneer

I was skeptical when I read I could cut stone veneer with a wet tile saw, but you really can (with Eldorado brand anyway!). I bought a new 7” diamond blade for our wet tile saw and made sure to go slowly. Some of the pieces were too thick to fit the full way under the guard, so for a few I had to flip the piece or get a little creative and hold it at an angle on the blade to get it cut (don’t worry, tile saw blades aren’t sharp so it’s not as dangerous as it sounds).

I also ended up buying this little handheld tile saw which was a big help. The hearth stone pieces couldn’t get through the stationary wet tile saw and my angle grinder wasn’t cutting it (literally), so I ran out to grab this tool. It hooks up to your garden hose to run water on the piece just like a regular tile saw would, and essentially is like a mix between a circular saw and a tile saw when it’s working.

The tile saw obviously cuts in a really clean straight line, which is not the same kind of organic rough edges as the rest of the stone veneer, so once I cut a piece I’d kind of chip away at the very edge of the cut with a chisel and hammer to knock away a few chips and give it more of a natural look.

Between those two saws and a trusty old chisel and hammer, that’s all you need to cut the stone.

The process from there is basically rinse and repeat until you’re done, but it’s not the kind of thing you can stop and start so I’d plan for about four hours of free time depending on the size of your space (that’s the maximum time you have to work with the mortar, anyway).

Next step: Grout

The next step in the process – once the stone has set for 24 hours – is grouting. Again, this is another personal preference – I’ve seen some fireplaces with almost no grout showing between tightly laid stones, some with an almost sunken look behind the stone, and the look I was going for: overgrouting, where it’s almost spilling out in front of the stones.

For me, the grouting (which is for some reason called grouting even though you’re actually using mortar), was a whole process, but I love how it turned out.

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