How to install mortarless stone veneer in your home
But what about a trend that started over the last decade and still seems to be growing in popularity? I’m talking about stone veneer without mortar. You may think it’s new technology, but it’s not. Not by far. The Egyptians used mortarless masonry on a large scale at Giza, home of the Great Pyramids. The pyramids had a smooth veneer of giant stone slabs without mortar.
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The same was done thousands of years ago at Machu Picchu high in the Andes. Plus, the people who built it did so without power tools, diamond wet saws, or abrasive dry-cut blades attached to a portable saw.
These two civilizations were not alone. There are many examples of stone walls, buildings and arches constructed without mortar. Instead, master stonemasons took the time to fit the stones together like pieces of a high-quality jigsaw puzzle. The good news is that you can purchase stone veneer for your home and follow in the footsteps of the master builders of old.
Recently, a woman who listens to my live stream on my Ask the Builder YouTube channel shared how she uses thin pieces of interlocking natural stone as a frame for her new fireplace. The old chimney developed a crack in the combustion chamber and had to be replaced. What is interesting is that the hearth and the wall above the fireplace were covered with large pieces of multicolored slates which are not replaced. The new stone veneer around the fireplace blends very well with the existing slate. Don’t be afraid to mix different stones, textures and sizes.
A few months ago, a close friend of mine inherited an oceanfront condominium in Southern California that was built over 40 years ago. The indoor fireplace had a dated tile surround, and it was time to replace the tiles. He and his wife chose to use thin stone veneer without mortar, which she installed. The color was fabulous and the 1 ½ inch tall stone pieces were the perfect scale to match both the room and the fireplace. After the job was done, she told me how easy it was to work with the stone.
Keep in mind that this material can be used outdoors with great success, provided you install it correctly. A few miles from my house, a new building sports a mortarless stone veneer about 1 ½ inches thick. Natural granite chunks have a random texture exposed to the weather.
Although it looks like the stone chunks are random in size, they are not. The various sizes were saw cut in a factory to precise dimensions, so you can stack the stones randomly and never worry about a gap. It is very similar to a cut stone pattern in a slate floor.
There are different ways to install these stone veneers. Some come in the form of panels that you screw to the wall. Others are individual pieces that you glue to an interior or exterior wall with Portland cement-based thin mortar or traditional brick mortar applied to the back of each piece. If using traditional mortar, add hydrated lime. I have a formula for this at AsktheBuilder.com.
The cumulative weight of the stone veneer is considerable. Most natural stones weigh around 150 pounds per cubic foot. The stone that surrounds the two fireplaces I mentioned earlier could easily weigh around 600 pounds. This means that when you install the stone, the first row must be strong and able to support the weight of the stones when you stack them.
When using a mortarless stone veneer on the exterior to mask a bland concrete foundation wall, it is beneficial to have a small shelf or ledge cast in the concrete. Craftsmen who build poured or poured concrete walls can do so with minimal effort. All the weight of the stone is then transferred to the sole, and there is little danger of the veneer failing in the future.
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Make sure your architect allows the face of your sheathed exterior frame walls to be flush with the overall face of the stone veneer. This is easily achieved by using a wider bottom plate. If your exterior siding is wood, vinyl, fiber cement, or something similar, it can overlap the stone veneer just as roof shingles overlap the course below. This is essential to ensure that no water enters the timber frame that may make up your exterior walls.
As with any product, be sure to read the installation instructions. Don’t expect the job to be done well. The instructions are easy to understand. Meet with the contractor or stonemason before beginning this phase of work and review the instructions. Remember: you should only hope for things you can’t control, like the weather. You can control how work is done on your home.
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