Step-by-Step: Installing Slate Stone on a Wall

Installing slate stone on a wall can transform your space into a luxurious, timeless retreat. This natural stone's durability, unique texture, and rich color palette make it an excellent choice for both interior and exterior surfaces. Whether you're creating a feature wall in your living room or updating your outdoor patio, follow this comprehensive guide to install slate stone like a professional.

Before you begin, ensure you have the right tools and materials. You'll need slate stones, thinset mortar, a trowel, a notched trowel, a rubber grout float, a grout sealer, safety glasses, and gloves. Also, measure your wall to determine how many slate stones you'll need, adding a few extra for waste.

Preparation and Layout

Proper preparation is key to a successful slate stone installation. Start by cleaning your wall surface to ensure good adhesion. Remove any old wallpaper, paint, or dirt, and let the wall dry completely.

Lay out your slate stones on the floor to plan your pattern. Slate comes in various shapes and sizes, so consider using a combination of patterns like herringbone, stack bond, or offset to create visual interest. Mark the back of each stone with a pencil to indicate its position in your pattern.

Mixing Thinset Mortar

Thinset mortar is a cement-based adhesive specifically designed for installing natural stone. Follow the manufacturer's instructions to mix the thinset with water, ensuring it reaches a consistency similar to peanut butter. Allow the mixed thinset to rest for 10 minutes before using it.

When mixing thinset, consider the size of your wall. A 50-pound bag of thinset typically covers about 25-30 square feet, depending on the stone thickness and pattern. It's better to mix a little extra than to run out mid-project.

Applying Thinset Mortar

Using a notched trowel, spread the thinset mortar onto the back of your slate stone, ensuring full coverage. Hold the trowel at a 45-degree angle and press the notches firmly against the stone to create grooves. This technique, known as "scratching," helps create a mechanical bond between the stone and the mortar.

Next, apply thinset to the wall using a square-notched trowel. Spread the mortar in small sections, about 3' x 3', to prevent it from drying out before you can install the stones. Hold the trowel at a 45-degree angle and use the notches to create grooves in the mortar bed, similar to the process on the back of the stone.

Installing Slate Stones

Press the slate stone firmly into the thinset-covered wall, using a slight twisting motion to ensure full contact with the mortar bed. Align the stone according to your planned pattern, using the marks on the back of each stone as a guide.

Continue installing stones, working from the bottom up and from one corner to the other. Stagger the vertical joints by at least 6 inches to create a strong, stable wall. Use spacers between stones to maintain consistent grout lines, typically between 1/8" and 1/4".

Cutting Slate Stones

To cut slate stones, use a wet saw equipped with a diamond blade. Measure and mark the stone where you need to make the cut, then secure the stone to the saw's base. Slowly lower the blade into the stone, allowing the water to lubricate the cut. Once the blade has reached the desired depth, turn off the saw and allow the stone to cool before removing it.

Alternatively, you can use a snap cutter or a guillotine cutter for straight cuts on thin slate stones. However, these tools may not be suitable for intricate cuts or thick stones, making a wet saw the better option for most installations.

Letting the Mortar Cure

Allow the thinset mortar to cure for at least 24 hours before applying grout. This allows the mortar to develop its full bond strength, ensuring your slate stones are securely attached to the wall. During this time, keep the installation area clean and free from moisture to prevent premature curing.

Once the mortar has cured, use a damp sponge to clean any remaining thinset from the surface of the stones. Be careful not to remove the thinset from the joints, as this can weaken the bond between the stones and the wall.

Grouting and Sealing

Mix sanded grout according to the manufacturer's instructions, adding a grout sealer to enhance stain resistance and durability. Use a rubber grout float to spread the grout diagonally across the joints, working it into the spaces with a pushing and pulling motion.

Allow the grout to set for about 15-20 minutes, then use a damp sponge to remove excess grout from the surface of the stones. Rinse the sponge frequently to prevent grout buildup, and be sure to clean the joints one last time with a damp, wrung-out sponge to remove any haze.

Sealing the Grout

Once the grout has cured for at least 72 hours, apply a grout sealer to protect it from stains and moisture. Use a clean cloth or sponge to apply the sealer evenly across the grout lines, following the manufacturer's instructions for application and drying times.

Allow the sealer to cure completely before exposing the installation to moisture or heavy foot traffic. This final step ensures that your slate stone wall will maintain its beauty and durability for years to come.

Congratulations! You've successfully installed slate stone on your wall, transforming your space into a stunning, timeless oasis. Now, sit back and enjoy the fruits of your labor, knowing that you've created a durable, low-maintenance surface that will stand the test of time. If you're feeling inspired, consider tackling another DIY project to further enhance your living space.