Slate’s Subtle Surprises

November 3, 2004

However, with a rainbow of colors being imported from all over the world, it’s also finding itself surrounding fireplaces, serving as wall cladding and flooring – and even appearing as an alternative to granite or marble in kitchens and baths.
As with other natural stones, not all slates are created equal. For the fabricator or designer willing to get acquainted with the product, though, it’s an attractive alternative to a customer looking for something outside the norm.

VARIETY SHOW
Depending on where you are in the country, slate can be as comfortable as an old shoe, as cutting-edge as tomorrow, or merely an unknown commodity.
For designers such as Diane Tardif of Woodstock Kitchen and Bath in Essex Junction, Vt., and McKee Patterson, a principal with Austin Patterson Disston Architects in Southport, Conn., using slate is almost a given.
“If you have a kitchen and you want it to have a quiet aspect, then slate is nice to use,” says Tardif. “I’ve also used it in bathrooms, especially in period homes, although people usually want a little more splash, a little more reflective light there.”
Tardif adds that in New England, it’s not unusual to find homes where slate roofs and slate sinks have lasted a century or longer. In fact, that’s part of the stone’s appeal.
“Of course, it’s New England slate,” she observes. “It’s real rugged, and the only veined stone in the world that can’t be harmed by acid or heat staining. That’s why it’s used a lot of chemistry labs.”
Patterson says his practice also takes the stone outside the kitchen and bath.
“We do use it in kitchen counters, but we also see it a lot in floors and as cladding in various places, like a veneer,” he says. “We also use it in backsplashes and walls. We love the stuff, because it’s subtle, not glitzy.”
As with Tardif, Patterson says his slate-of-choice is quarried from Maine to northern New York. By buying regionally, it also allows him to call the quarries and get the stone in custom thicknesses.
Slate might drip with tradition on the East Coast, but across the country in California, David Dills, the Los Angeles-based general sales manager of American Slate Co., says slate has developed a good presence that’s a little trendier.
If anything, the presence of the stone in such popular West Coast eateries as P.F. Chang’s and Noodles is making more people think about bringing it into their own homes.
“We’re always trying to reinvent the wheel here, and come up with something new and hip,” says Dills. “But, if people aren’t thinking about slate, they probably aren’t on the cutting edge because you can’t open up a design magazine and not see it, especially in the kitchens.”
Dills is in the process of remodeling his own kitchen, and he says one popular West Coast lifestyle magazine features slate is fully a third of its kitchen designs. However, American sells nationwide, and he acknowledges that isn’t the case everywhere.
“As you move toward the Midwest, just like with so many other design trends, there seems to be less product available to them,” he says.
Still, Price Wills, the Bozeman, Mont.-based owner of Montana Tile and Stone, regularly sells slate to his customers and often specifies it. He believes the biggest drawback to getting slate into more homes is that it’s still below the radar of many designers and specifiers.
“The only reason I can think of that they choose not to use slates or show slates is they haven’t been accustomed to specifying them,” he says. “Given the nature of the stone – its colors, textures and immense variety – they should, though.”

PLENTY OF PLUSES
Colors? Textures? Variety? Those surely aren’t generally associated with slate, and that’s just the beginning. If anything, misperceptions about slate run rampant, and probably do contribute to its small share of the natural-stone market.
“I often hear this from people who walk through the door,” Dills says. “We’ll say, ‘What about slate?’ They’ll go, ‘It’s slippery, or it’s too soft or it’s really porous.’ It’s really the exact opposite, but there’s not much good geologic knowledge or technical knowledge of this product, even in the industry.”
John Tatko, the general manager of Sheldon Slate Products Co. Inc.’s plant in Monson, Maine, says that – due to geological factors – not all slates are alike.
“The mountains here in New England are very old, geologically speaking,” he explains. “If you look at slate as being a lot like cake, a lot of these other slates haven’t been baked enough, while others have been baked almost to the point of being brittle. Ours is baked just right.”
Woodstock’s Tardif, a Sheldon customer, says she often turns to that company’s products because of the fact that they’re so dense they can’t be harmed by heat or acid.
“On a per-square-inch-basis, it’s much denser than granite,” she says. “I could take a 4’ X 8’ X 1 1/4” slab of granite, suspend it from two objects, jump on it, and break it very easily. Even with a smaller piece of slate, it won’t break.”
American’s Dills says another important attribute of slate is its low porosity – a characteristic that makes it less prone to accepting stains.
“Most granites are in the three-percent range,” he says. “With slates we’re talking about under a quarter-of-a-percent water-absorption ratio, so stain resistance is extreme.”
One concern often raised about slate is that it’s a soft stone that can be scratched or marred easily. While that isn’t necessarily a concern with floors, where use provides character – or with walls or backsplashes, which shouldn’t be exposed to scratching – it does generate mixed reviews of slate for kitchen countertops.
“If you chip a floor or put a scratch it in, it isn’t going to affect the beauty,” says Mark Wennstedt, president of Source Products Group, a slate supplier based in Broomfield, Colo. “I think there are better products out there for kitchen countertops just because it’s a softer stone.”
Montana Tile’s Wills agrees, saying, “Slate isn’t a good kitchen counter surface because it’s too soft; it will take on scratching.”
“It can scratch,” concurs Tardif, who has a slate sink and countertops in her own kitchen. “But, you can just wipe it down. It’s very little maintenance, and because it’s not shiny it doesn’t show things like a shiny surface does.”
Although they disagree on its use for countertops, Wennstedt says those particular attributes make slate a very attractive product for kitchen floors.
“Because of the multicolored nature of the product and the texture, it doesn’t appear to be dirty,” he says. “If it’s installed properly and sealed properly, the maintenance can be very, very simple, and because it has a clefted face, it gives more slip resistance.”

COLORFUL PALETTE
Possibly the worst assumption many people make about slate is that it doesn’t offer much in the way of a color palette. While the palette for native slates isn’t huge, it does offer some nice variations, and slate from around the world offers an amazing range of hues.
Tardif says just from this country she’s utilized slates that are black, red, mottled purple (green and reddish-purple), variegated purple (reddish-purple with a little green), and lighter and darker shades of green.
“I’ve also used a dark gray that came out of Pennsylvania, which is the one we have on our floor,” she says. “It’s not the same as the black slate from Maine.”
And, Tardif says she’s utilized a black slate from Italy that was used by one client on a vanity that she describes as, “really beautiful.”
Other sources of black slate include Asia and Brazil. Beyond that, slate offers shades of the three primary colors – red, yellow and blue – and multicolored options. For instance, America’s Dills says one product popular with that company right now is a wildly multicolored stone from China.
“It really is up to whatever color palette the designer is trying to achieve,” he says.
“When I suggest slate, I’m also keeping in mind that color is one of the reasons for suggesting it,” says Austin Patterson Disston’s Patterson.
While the colors are there, a bigger concern for stone sellers and specifiers is making sure the slate being used on a project is a good stone. Because slate is a sedimentary rock that’s undergone metamorphosis, it has a natural cleft, and can’t just be pulled from the ground and sliced up any which way.
“Until recently, it was very difficult to maintain in slab form,” says Dills. “You have to get deep enough into the ground to where the product is dense enough to pull out in large sheets.”
That, in turn, has led to some inferior products finding their way onto the import market. It’s not uncommon for the overburden that’s removed in getting to the really dense layers of slate to be processed and sold, especially in Third World countries. Often it shows up in home building centers in this country.
“I get calls from people who purchase slate at building centers and then complain it’s horrible,” Dills says. “They couldn’t install it; it just flakes.”
For stone professionals who are buying from reputable suppliers, he adds that one good way to ensure you’re purchasing good, dense slate is to ask for the ASTM testing data on that specific product. Buying from an importer that can provide good calibration is also important.

DREAM STONE?
For the most part, slates fabricate and install much like other natural stones. The softness of the stone, coupled with its density, makes it fairly easy to work and handle.
Woodstock’s Tardif says she has a couple different fabricators she works with, and Sheldon Slate also does fabrication.
“It’s easier to work than granite because it’s not as fragile,” she says. “The big issue with slate is crating and shipping. All stone is heavy and expensive to ship, but slate is heavy.”
“The mechanics of fabricating slate are the same as with granite or marble,” says Sheldon’s Tatko. “Everything is wet cut with diamonds, and all our finish polishing is done with diamond pads.”
Because of its density, Dills says fabricators often find the work, “a little slower moving,” but he’s received few complaints from his customers on the way the stone works.
While slate can be polished, a honed finish is much more common, despite the fact that because the color comes from striations in the grain honing will tend to knock down the color in a given piece.
Edging some slates can also offer a challenge, says Montana Tile’s Wills.
“Because the stone is soft by nature, your front edge may take on a different appearance,” he says. “When you polish the edge and bring it up to a high hone, in some stones it won’t have the same coloration as the top. Fortunately, having the two look different is actually quite elegant.”
Slate can also be worked with other accepted methods for decorating other natural stone, including sandblasting and waterjet cutting. For example, both Sheldon and Source Products sell slate tiles with added decorative images.
Again, because of their density, installing fabricated slate slabs isn’t a problem, either.
“They’re lighter in weight and they accept basins very nicely,” says Wills. “There’s really very little problem from the shop to the customer’s home.”
“Installation really just takes good, basic common sense and the skills of a good carpenter,” says Tatko. “We send jobs all the time to people who have never seen and worked with the material before.”
The price of slate varies, of course, by supplier. As with most other natural stones, imports are less costly than domestically produced materials. A good rule of thumb, those who work with it regularly say, is to figure on paying about the same as you would for a moderate to higher-end granite.
While those price points may not make slate every end-user’s dream stone, it does have a lot to offer the right buyer, and those who sell or specify it say it isn’t going away.
“Once we get a fabricator who uses it and they buy some of our material, it’s very common that they order again,” says Tatko.
Wills estimates as much as 30 percent of his total sales are in slate, and he says that’s grown each of the seven years since he started his business.
“We tend to distribute quite a bit of slate and a fair amount of slate slab,” he says. “It’s a beautiful stone and I think like any beautiful stone, it withstands the test of time.”
Source Products’ Wennstedt says that people laughed when he began selling slate in the 1980s because many felt it was a dead product. Instead, he says he thinks it’s taken awhile to develop the marketing to really catch the eye of the buying public.
“As we’ve grown and expanded, the market has grown and expanded, as well,” Wennstedt concludes. “Natural stone is going to continue to be a big part of the marketplace and slate will be there, just because of its characteristics, great colors and texture.”