Spring 2008
New uses for an old stone
Flagstone makes a bold statement in this residential landscape design.
Photo courtesy of Silverado Building Materials
By Gail Snyder
In 1991, The American Institute of Architects recognized Frank Lloyd Wright, controversial architect of the early 20th century, as "the greatest American architect of our time." Wright espoused "organic architecture," meaning design and structure that promoted harmony between man and nature by using the natural materials of the immediate, surrounding environment. One can understand why flagstone, a plentiful and widely available material, emerged in many of his most acclaimed works: the flagstone floors in the cantilevered Fallingwater, the flagstone patio in sand and grass at Kentuck Knob and the terraces of his Taliesin Estate.
Quarried throughout the United States and the world (such as along the west coast of Ireland), the abundance of flagstone and its widespread locations for quarrying make it the perfect fit for followers of Wright's organic architectural theories, but most of its growing popularity stems from its attainability and flexibility. In fact, as the trend for the use of natural materials in the construction of our living spaces grows, flagstone is expanding its horizons. No longer limited to the role of patio paver, walkway step or landscaping stone, this flat rock is now appearing in both interior and exterior scenarios. In pool decks, barbecue grills, floors, kitchen interiors, countertops, driveways, fences, roofing, potting benches, even furniture, flagstone is making a new name for itself, but what is it really?
This patio was created with flagstone pavers, a traditional and popular use for the natural stone.
Photo courtesy of Earthworks Inc.
A Rock by Any Other Name
"A flagstone is any natural bed material that is quarried in layers, usually anywhere from 3/4" thin up to 2/12" to 3" thick. The difference between sandstone and limestone is really not a big one and a tremendous amount of both is available," explains Russ Stout, sales manager for Earthworks Inc., in Perryville, Mo. "For example, in the northern areas of the United States, such as the Wisconsin region, you'll find an abundance of limestone flag. In the Oklahoma region, there is a tremendous amount of sandstone flag. There is also some volcanic flag in Mexico, and granite flagging material as well."
Flagstone is not slate, though the layperson commonly confuses it with same. While like flagstone, slate is a sedimentary rock; it is a foliated, metamorphic rock commonly composed of clay and volcanic ash. Flagstone, on the other hand, is an essentially quartz sedimentary stone that is quarried and split into layers for multiple uses. Terminology is largely determined by locale, according to Liz Serven, manager of Silverado Masonry Design Center in Sacramento, Calif., and a member of the Building Stone Institute's board of directors. For example, the word fieldstone is used (typically along America's eastern coast) to denote a boulder-like building stone. However, in the West, fieldstone is a mossy flagstone, sometimes called moss rock, Cold Water Canyon Flag or Nevada Moss Flag. The terms "flagstone" and "sandstone" are also often used interchangeably because of flagstone's predominant composition of sandstone mixed with feldspar and quartz, fused with calcium, silica and iron oxide.
Designer and sculptor Dwayne Scott Cranford creates flagstone furniture, revealing how durable and functional this natural stone can be.
Photo courtesy of Dwayne Scott Cranford
These binding materials and the location of the quarry determine the variable structural stamina and shades of flagstone. The lands of Arizona, for example, hold an abundance of flagstone, usually in reds and buffs that cut well, yet are known for durability. The New Mexico buffs tinged with shades of tan and brown are beautiful but more difficult to find in stone yards, and the Pennsylvania Blue Flagstone reflects the color of its concentrated granite and feldspar content. Colorado flagstones primarily vary from buffs to reds, with some stones tinged with a golden hue. Because of the many possible combinations of binding ingredients these stones may also be pink, peach, chocolate, green, gold, beige and white.
Some of the quarried pieces contain the fossilized tracks of ancient insects and that the interior rooms of European castles of the Middle Ages contain flagstone flooring and cladded walls (walls embedded with flagstone mosaics). In fact, as the movement toward using natural materials continues, flagstone can be an economical option. "The budget conscious can do a mosaic look on their walls and get greater coverage and a better bang for their dollar with flagstone versus using a thick ledge stone or a building stone," Serven explains. While the mineral makeup of flagstone allows for a varied palette, the mineral content also dictates other properties that must be considered in order to choose the correct flagstone for a project.
Designer and sculptor Dwayne Scott Cranford creates flagstone furniture, revealing how durable and functional this natural stone can be.
Photo courtesy of Dwayne Scott Cranford
Take a Seat
Designer Creates Flagstone Furniture
Several years ago, Dwayne Scott Cranford, designer and sculptor, was staying busy with gallery shows around the country featuring his steel sculpture, when a relaxing moment inspired a new product. "I was sitting in my patio furniture one day and noticed how cheaply made it was, and I thought about how I had to store it for most of the year," he says. "I wanted to come up with a functional but artistic type of patio furniture, and I always had an infatuation with somehow incorporating stone with steel. So I started working with the idea and made it what it is today."
Today, the end product is durable and unique furniture of stone and steel or stone and powder-coated aluminum (available in numerous colors), which is most popular in coastal areas because it weathers the elements better than powder-coated steel. Using special tools, Cranford drills into the rock and permanently attaches it to the metal using a stainless steel insert bonded within the stone. The artist uses granite, jade and marble, but he particularly enjoys using flagstone. "Flagstone is flat already, so I don't have to cut it, although I do cut it to shape. It also had to have a certain strength, so I mainly use buff, blonde and red flagstone from Colorado and a gray flagstone sourced from Idaho," he says.
The often asked question is, but is it comfortable? "It's surprisingly comfortable," says Cranford. "If it wasn't, I wouldn't be selling it, and if I wasn't selling it, I wouldn't be making it." In fact, Cranford receives orders from around the country and has seen his handcrafted furniture (including tables, chairs, swivel chairs, patio sets, benches, coffee tables, loungers and ottomans) used on houseboats, in tree houses, in breakfast nooks, sunrooms and foyers. A chiropractor has even approved the furniture for its ergonomic comfort.
The furniture, though made with ancient stone, has a modern flair, and luckily, can survive almost any storm. A chair with arms, for example, weighs about 180 pounds. "People ask how they can move it around, but that's the whole point of it. For 12 months out of the year, you can leave it outside, no matter where you live. The most maintenance you have is to maybe hose it off. The stone is already about 2.4 billion years old, so what does it matter?" Cranford says.
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How to Choose
The form and function of a project should be the primary consideration when selecting the right flagstone. For example, a flagstone that works well in one climate may be totally unsuitable for another. "One thing you want to take into consideration is its pre-saw cycles," Stout says. "You don't want to use a soft limestone content or soft sandstone content flag material in a very active pre-saw environment where separation of the bedding seams may occur. And, you wouldn't want to take a highly absorbent material and do an install in Chicago where hard freezes would cause separation or deterioration of the stone. You have to be more selective in your different market areas and consider what the climate conditions are. For example, we've recently completed some driveways, which require a specific type of durable flagstone. You would do a sand set or lay it in a mortar bed on those applications."
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Pennsylvania Bluestone creates a natural-looking walkway when cut into flagstone.
Photo courtesy of Earthworks Inc.
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So how does a do-it-yourselfer or even professional installer select the right pallets of stone for a specific job? Talk to a qualified stone salesman who is schooled in the intricacies of quarry operations and factors such as water absorption, stone content and sedimentary/layering properties. Also, discuss your project in terms of where you plan to place the stone, the climate and the installation type — in sand, cement or mortar for example. "A typical installation is on sand versus concrete," Serven says, "so they will need to know how they are applying it before they speak to a dealer. The quartzites are the hardest and the sandstones are very soft, which means that the sandstones will stain faster than the quartzites." The idea of staining opens up what appears to be a big controversy in the world of flagstone.
To Seal or Not to Seal?
That is the question that, according to flagstone vendors, is asked on a daily basis, and the answer is in hot dispute. Some vendors are awaiting not only a comprehensive article, but an entire book on that subject. "You'll talk to one stone person and they'll say seal everything. Another one will say, 'Let stone be stone. Don't seal it, let it breathe, and allow it to operate the way God meant it to,'" Stout says.
The decision may all boil down to personal preference and application type. In high-traffic, new construction areas, where a sand fit will be used in a pathway for example, Stout recommends using polymeric sand and sealing the stones. "That way you aren't tracking sand into the interior of the building or home during new construction, because over time, it's going to bond itself up anyway and this just accelerates that process. If you want a wet look to make the color of the stone stand out, apply a wet-look sealer to it. It depends on what your likes and dislikes are," he states.
Flagstone adds color and depth to a covered patio feature.
Photo courtesy of Earthworks Inc.
Natural stone with a weathered patina is the low maintenance option for pathways, walkways, even meditation areas that can easily be managed year-round with nothing more than occasional water wash. However, Serven highly recommends using a sealer in entertainment scenarios such as outdoor kitchens. Here a sealer doesn't guarantee against stains, but allows some time for a quick clean-up from a grease splatter or a red wine spill. "The best way to make the decision is to ask yourself, 'Why am I sealing it?'" she says.
Whatever the decision may be, flagstone experts Hans Clausser and David Clausser of www.the-flagstone-experts.com advise waiting at least two weeks after project completion to allow moisture evaporation before applying sealer to a flagstone project. Then use a sealer that allows moisture out, but not in. Above all, they recommend never succumbing to the temptation to use urethane sealers because they don't allow the stone to breathe. Plus, urethanes leech the alkaline from concrete, causing nasty gray blotches on the stone.
A low-maintenance option for pathways, walkways and even poolside surrounds, flagstone adds beauty to any outdoor space.
Photo courtesy of Silverado Building Materials
Coverage and the Cutting Edge
"Because stone naturally varies in color, thickness, size and shape, it's very important to know the thickness allowances that you're looking for," Serven advises. "A masonry dealer can help you determine the quantity for a project, because in the industry there are standard coverages for most stone." Usually figured on a per-ton basis, an inch and a half flagstone will cover approximately 120 square feet per ton. Flagstone also has a natural cleft, or surface irregularity, so the product is measured from the highest point of the natural clefting to the bottom with a standard variation of plus or minus a quarter of an inch, an important fact to know during the selection process.
The irregular, mosaic shapes of quarried flagstone are the most popular and probably more economical, but even the mosaic shapes must be cut for applications such as stairways and walkways to give the enhancing puzzle-fit appearance. For this reason, before finalizing a project, one should lay out the existing stone pieces and determine the pattern to minimize the need for cutting. Pre-planning by matching adjacent stones means that irregular stones will have to be cut once, maybe twice, or possibly not at all.
This red flagstone walkway adds color to an otherwise neutral palette.
Photo courtesy of Loukonen Bros. Stone
But is it Green?
The use of natural building materials may reflect the national effort to create environment-friendly buildings and homes. Of course, flagstone is a natural material, but whether it's really "green" depends on how it is quarried, fabricated and shipped. The concept of "organic architecture" is somewhat mitigated when materials have been transported for long distances using the energy and fuel consumption required for same.
"Most flagstone is a localized material, but everybody wants what they don't have, so it is shipped from all over the United States and beyond," Stout says. And many other considerations come into play such as whether the quarries are accredited, permitted and bonded; and whether they are following state and national guidelines with a reclamation process on file. Once installed, however, you can't take the green out of natural stone.
To Each His Own
Flagstone has another characteristic that makes it all the more in demand: its one-of-a-kind properties. "Because stone varies in color, thickness, shape and size, we do not pick a pallet of stone for customers even if they've selected the variety they like from the showroom floor. Everybody has to pick their own pallet," explains Serven. For every stunning project — a wall, a patio, a driveway or even furniture — builders and homeowners will know that when using flagstone, the exact look will never be duplicated. "In the quarrying process, we may get down another 50 feet and the stone totally changes color," Stout remarks. "One thing about flagstone is that when you get a piece of it, it is unique. There's not another one like it, I promise you."
Gail Snyder is an Atlanta-based freelance writer.
Resources
Earthworks Inc.
Russ Stout
Perryville, Mo.
800-887-4555
www.ewgroupinc.com
Silverado Masonry
Design Center
Liz Serven
Sacramento, Calif.
916-381-8711
www.silveradonline.com
Stone2Furniture
Dwayne Scott Cranford
Livermore, Colo.
866-407-8991
www.stone2furniture.com
www.the-flagstone-experts.com
Hans Clausser
David Clausser
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