There's something so homey about a stone fireplace, bringing to mind cozy nights spent with loved ones in front of a blazing hearth. For those who think that using real stone is the only way to get this look, think again: Today's cast-stone veneer looks a lot like the real thing, with styles ranging from stacked stone to river rock. And if its nicer price tag makes it an option that's hard to pass up, the DIY-friendly installation will seal the deal.
How Do You Attach Stone Veneer to a Fireplace?
As senior technical editor Mark Powers shows us, it takes just a few days to build a base for the stones and mortar them to your fireplace for a timeless look that will warm up your holiday gatherings for years.
Overview of a Stone Veneer Fireplace Surround
- Friday: Apply the builder's felt, metal lath, and scratch coat, which will dry overnight.
- Saturday: Install the stones and clean out the joints between them.
- Sunday: Grout the joints.
Add the Base Layers: Install Builder's Felt
Working from the bottom up, staple horizontal lengths of builder's felt to the front and sides of the fireplace where the stones will go, overlapping the lengths by 2 inches or more. Each length of felt should be a continuous single piece so that water in the mortar can't seep behind the felt and cause damage.
Secure Metal Lath Over the Felt
One side of metal lath has cuplike protrusions that keep mortar in place. When installed, this side should face forward, with the "cups" facing up; it will feel rough to the touch when you run your hand down the wall but smooth in the opposite direction. Nail horizontal lengths of lath directly into the wall's framing on the front of the fireplace, overlapping each piece 2 inches or more and spacing the nails 6 inches apart. Then bend the lath around the sides of the fireplace, using a scrap piece of wood to help if needed, and nail it to the framing on the front and side walls to keep it in place and prevent the mortar from cracking.
Apply the Scratch Coat: Cover the Lath with Mortar
Mix veneer mortar to the consistency of creamy peanut butter. With a finishing trowel, spread it over the lath, first using a downward motion to "fill" the cups, then building the surface to a thickness of ½ inch by using a side-to-side or fanning motion to spread more mortar over the first layer.
Comb the Scratch Coat
While the mortar is still pliable (about 20 minutes after application), comb it horizontally, using the notched tiling trowel held at a slight angle to the surface. These grooves create a textured surface for the mortared stones to grab on to. Allow the scratch coat to cure overnight (or longer).
Prepare the Field of Stones: Create a Dry Run of Your Design
Selecting and laying out the stones on a template helps you visualize how they'll look installed. Tape plastic sheeting or an old drop cloth to a flat surface, and use painter's tape to outline the shape of your fireplace on it. Begin by placing the corner pieces that will wrap the opening and sides of the fireplace. Then fill in the rest of the field, leaving a joint about as wide as a finger between each stone and staggering stones of different sizes, shapes, and colors to achieve the look you want. The corner pieces used for the header at the top of the fireplace opening will be installed vertically instead of horizontally, so opt for stones of similar height in this area.
Score the Corner Pieces
This is the first of two steps for cutting the stones to size. Measure the depth of the fireplace opening on the top and sides, making sure to leave enough clearance all around to remove the doors or screen if necessary once the stones are in place. Mark the measurements on the corresponding corner pieces, starting at the inner corner of each stone's back side. Using a grinder, score the back sides to a depth of about half their thickness. Then measure the depth of the fireplace's sidewalls, and mark and score the remaining corner pieces in the same manner.
Remove Excess Material From the Corner Pieces
Hold a stone so that the waste side hangs over the edge of your work surface. Strike the waste side with a brick hammer to create a natural-looking split. Repeat for all corner pieces.
Install the Corner Pieces: Wet the Stone and Wall
You'll install the header first, so start with the left-side corner piece for this area. Using a spray bottle or damp sponge, dampen the back of the stone and the area on the wall where the stone will be placed. The moisture will help the mortar cure more slowly for a stronger bond.
Coat the First Corner Pieces for the Header
Mix mortar to the consistency of pudding. Using a brick trowel, apply a ½- to 3/4-inch layer to the back side of the first corner piece, using a pushing motion to work it into both surfaces until they're completely coated. Then, with the trowel's tip, use a pulling motion to make a furrow in the center of the mortar on each surface. Don't let wet mortar drip onto the face of the stone, because it will create stains.
Install the Header Stones
Press the stone firmly into place on the top-left part of the header. Wiggle it back and forth slightly, and stop pressing when you can feel the stone touch the top of the scratch coat. Mortar should ooze from all sides of the stone as you do this. Repeat with the remaining header stones.
Tip: Don't try to wipe wet mortar off the face of cast stone—you'll end up pushing it deep into the stone's surface pores, where it will cure and create blotches and stains that are impossible to remove. Instead, let the mortar dry and brush it off with a whisk broom.
Install the Rest of the Corner Pieces
Back-butter and install the rest of the corner pieces that wrap the opening and sides of the fireplace, using the process described above. Leave a finger's-width joint between each stone.
Fill in the Field: Coat the Top-left Fieldstone
Starting at the top-left portion of the field, back-butter the stone using the process described in Step 10. Again, don't let wet mortar drip onto the face of the stone.
Install the First Course
Press the stone firmly into place at the top of the field, almost touching the ceiling. Wiggle it into place until it sits against the scratch coat. Mortar should ooze from all sides of the stone. Repeat for the remaining stones in the first course, leaving a finger's-width joint between each stone.
Finish the Field
Continue adding stones from the top down, which will keep mortar from falling onto the face of the stones below as you work. Again, leave a joint as wide as your finger between each stone. Dress the ends of any cut stones by applying extra mortar to them. Before you finish for the day, remove excess mortar between the stones with a striking tool and whisk broom so that there's enough room to add fresh grout tomorrow. Let the mortar cure overnight (or longer).
Tip: Pay attention to the size, color, and shape of the stones as you install them. Don't be afraid to change your original layout or cut the stones to size for better results.
Grout the Stones: Fill the Joints With Grout
Cut the tip off the end of a grout bag, sizing your cut to the joint width. Fill the bag halfway with fresh grout mixed to the consistency of pudding. Twist the wide end of the bag shut, and squeeze grout toward the tip until all the air bubbles are gone and the grout reaches the opening. Starting with vertical "head" joints and moving on to horizontal "bed" joints, fill the joints with grout, always using an upward pulling motion as you work. (For the head joints, use a step stool if necessary to reach the highest stones.) Fill the joints until the grout is flush with or protrudes slightly from the face of the stones.
Strike the Grout
Let the grout cure until pressing it with a finger leaves a dent without breaking through the surface (about 60 minutes). Using the striking tool, carve the grout to the desired shape and depth. (You can use a store-bought striking tool, a chopstick, or the end of a 1x1 that's been rounded with sandpaper, depending on the size of the joints.)
Achieve a classic look by carving a grout profile that sits below the face of the stones; for a rustic effect, like the one we used, shape the grout to sit flush with the stones (known as an overgrout technique), then go over the grout lines with a whisk broom to create a natural-looking finish. Let the grout cure for at least 48 hours before using the fireplace.