Cork Building Materials Brattleboro VT
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Though bamboo has been touted lately as the renewable material of choice in green construction, there’s another sustainable material fashionably making its way into the eco-friendly limelight: cork. In fact, cork has been around just as long, if not longer, than bamboo.
Unlike hardwood flooring, which is harvested from trees that have to be cut down, cork comes from the bark of living cork oak trees indigenous to the Mediterranean region — primarily Portugal, Spain and Algeria. This entirely renewable material is durable and comfortable, and is an excellent insulator due to cellular properties that allow for the formation of air pockets within the cork.
Because cork is nearly 80 percent air, a cork floor’s cushioned, flexible surface is soft and warm underfoot, retaining heat in cold weather. Quiet to walk on and shock-absorbent, durable cork floors also are more scratch- and dent-resistant than many wood alternatives.
Benefits of Cork
Though cork floors have been around for decades, industry leaders predict a renewed interest in the material both commercially and residentially. Builders, remodelers and homeowners are seeking more renewable, environmentally friendly materials, and manufacturers are providing easier methods of installation, as well as a wider variety of designs and color.
“The use of these materials in place of conventional products can significantly improve the overall environmental performance of the home,” says Ashley Katz, communications manager for the U.S. Green Building Council. “Because cork is a rapidly renewable material, it can help earn a point within the LEED for Homes [Leadership in Energy and Environmental Design] rating system, which certainly is helping drive the interest in this material.”
“As the designer, architect and consumer understand the benefits of cork, there is a realization of the true sustainability of cork flooring,” adds Randy Gillespie, vice president of sales and marketing for Expanko, a Pennsylvania-based company that specializes in the production of sustainable flooring products. “In addition, cork tiles create a traditional look,” adding to a home’s overall design.
What’s more, cork is a safe, comfortable product, Gillespie notes. Consumers who are increasingly interested in products that are not only environmentally friendly but also “create a safe environment for our children and ourselves” will find cork a good option.
Historical records indicate cork was used for insulation and flotation devices as early as 3,000 B.C., with cork wine stoppers gaining wider use throughout the 18th and 19th centuries. Following the introduction of new technologies in the late 1900s for the processing and manufacture of cork products, cork was also employed for insulation purposes in military and commercial vehicles, and eventually found its way into the home flooring industry.
Without causing any harm to the tree itself, the cork oak’s bark is removed approximately every nine to 10 years, often beginning only after the tree reaches 25 years of age. Considering most cork oaks live to be 150 to 250 years old, these hardy trees yield multiple harvests throughout their lifetime. To preserve the tree’s natural defenses against pests and predators, no more than 50 percent of the bark is harvested at one time. And because the trees are naturally resilient to disease and insect damage, few if any pesticides and fertilizers are used.
After the cork tree bark is harvested, it’s left to dry for a few months, after which manufacturers may first cut out cork stoppers. The remaining material is ground up and compressed into tile molds, which are then baked in an oven using varying temperatures to achieve different shades of light or dark. Tiles also will vary in shade depending on whether they’re cut from the inside or the outer layers of the tree.
After they’re cut, the tiles are sanded and either finished or left unfinished. As an added advantage, typically all raw materials are consumed during the manufacturing process, leaving no post-production waste.
Colors of Cork
Some manufacturers, such as Expanko, produce only natural tiles without the use of any stains, dyes or coloring, while others opt to stain tiles (some with natural, water-based and fade-resistant pigments) in various colors. Most product lines offer up to 30 or more different looks.
Because cork is a natural product, homeowners can expect to see variations in the shade and pattern of the cork throughout the tile, as with any hardwood, stone or marble surface. Whether the manufacturer uses stains and dyes will determine the range of options available.
Some cork tiles mimic a marble, granite or stone finish, while others appear more like wood grain, such as Natural Cork’s parquet line. Tiles can also appear more granulated or pebble-like, though the surface is always smooth. Colors range from rich natural colors such as deep brown, caramel and coffee to red, orange and rust tones, as well as lighter, softer shades of gray, beige and ivory. Globus Cork boasts “any size, any color,” offering a variety of custom-dyed tiles ranging in color from lemon, tangerine and marigold to ocean blue, amethyst and ebony.
Depending on the manufacturer, cork tiles range in size from various rectangular dimensions in narrow or wide planks roughly 8-by-35 inches or 18-by-24 inches, respectively, to square tiles often 12-by-12 inches. Typically, tiles are about one-half to one-quart-inch thick and may come with a beveled edge. Manufacturers like Globus Cork also offer patterned accent pieces in a variety of geometric shapes.
Cork tiles are available unfinished or finished with a polyurethane or wax coat, depending on the company. Some companies offer finish options free of VOCs (volatile organic compounds), such as American Cork’s UV-cured acrylic. Cork tiles can cost anywhere from $5 per square foot to $9 or even $10 per square foot, depending on the finish, size and shape.
Installing Cork Floors
Traditionally, cork floors were installed using 12-inch square tiles that were glued down and then sealed with a topcoat. Nowadays, cork tiles also come in easy-to-install tongue and groove planks already finished, with interlocking joints so they can be floated over plywood, concrete or subfloors, as well as some types of existing flooring. With flooring options that simply snap together, without the use of glue or even nails in many cases, a variety of manufacturers offer DIY instructions for home installation.
If you’re planning to install your own floor, there are a couple of points you should keep in mind. Because the tiles can vary in pattern and color, you’ll want to lay them out ahead of time and consider their placement before you begin. Also, like any natural material, cork will expand and contract in cold and warm weather, so you’ll need to leave adequate space along the edges of the room beneath the molding to allow for minor shifting.
There are some advantages to choosing glue-down tiles over floating floors, however. “Expanko designs and supplies a homogenous cork floor tile [that] is not a veneer like bamboo, cork and even wood floating floors,” explains Gillespie. “The homogenous cork tiles are a glue-down product and can be sanded and refinished for 35 to 75 years of service.”
Cork tiles that can be sanded to extend their lifetime have the benefit of limiting construction waste, in addition to a longer product life, he adds.
Homeowners should be aware of the fact that water can damage cork flooring, so it’s not advisable to place cork in areas where water leakage may occur. Likewise, direct sun exposure may cause untreated cork tiles to fade more quickly.
Compared to most traditional flooring, cork flooring requires little maintenance and will usually last about 10 years before a new topcoat or replacement is needed, depending on the level of traffic in the area. Cork also is naturally antimicrobial and mold and mildew resistant, and acts as a natural repellant to termites and other common household pests, requiring only mild detergent and mopping for upkeep.
Given all these benefits, it’s no wonder more and more homeowners are choosing cork for their floors.