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Cork Flooring for the Commercial User
Copyright reserved by Jelinek Cork Group

Increasingly popular, cork flooring is no longer solely the domain of residential users, it is also being used more often in commercial settings not only because of the variety of unique tile designs and patterns but also the material’s many other properties.

Resilient and durable, cork tiles also have the benefit of being soft underfoot and providing insulation against hot and cold. They assist in both impact sound reduction (IIC) and sound transmission reduction (STC) plus are anti-allergenic and environmentally-friendly. Additionally, cork flooring is priced in a similar category to hardwood.

Restaurants, Gyms, and Offices

Cork flooring has been used in commercial environments for many years. For example, the old Toronto Stock Exchange building had cork floors, easing the joints of traders who were on their feet all day and providing a quieter indoor atmosphere than would traditional hard tile surfaces. In the 1950s, cork was frequently installed in restaurants, gyms and offices–anywhere people spend a lot of time standing.

Cork tiles installed at this time were considered “massive” tiles or solid with the same pattern all the way through. These tiles could be refinished just like a hardwood floor–sanded down and then varnished. They were extremely durable and were usually four to six mm thick.

As the years went by, cork tile manufacturers endeavored to reduce costs by replacing massive tiles with a veneer pattern on the surface of a composition cork base and by decreasing the thickness of the tile to 2-mm. In addition, the flooring adhesives used for cork tiling changed from a toxic, but extremely strong mastic to a more modern flexible urethane. These changes sometimes produced undesirable effects such as the tiles breaking apart during installation and lifting after installation. The cork flooring industry reputation suffered and sales of cork tiles declined.
 

Cork Today

As the mistakes of the middle years of cork flooring were realized, manufacturers adjusted and cork made a comeback. Throughout the 1990s, sales of cork floors rose exponentially, a trend that continues today. The lessons of the past created firm rules for the future and today’s installers can rely on trouble free installations that highlight every advantage of the product.

Today there are two types of cork flooring products on the market suitable for commercial environments. The first is the standard “glue down” tile. These tiles are usually 12 sq. in. and 4-mm thick, although they are available in larger sizes, with and without beveled edges, and in an assortment of shapes. They are purchased either massive (same pattern all the way through) or with a veneer surface pattern. For a commercial application that may involve refinishing years down the road, the massive tile is the best selection because the tile can be refinished through sanding. The tiles come either unfinished or factory pre-finished, which involves three coats of UV-protected polyurethane.

The second type of cork floor tile available today is a floating cork floor plank. Similar to laminate wood floor planks, the floating cork floor plank consists of a cork base that is typically 2-mm thick, a center core consisting of MDF fiberboard, and a 3-mm surface layer of cork in a variety of patterns. These tiles are normally always purchased pre-finished with three coats of a UV-cured polyurethane. They are installed tongue and groove style using the same procedure as the installation of a laminate floor. The engineered design reduces the number of variables that are factors for a successful installation. For example, expansion is hardly an issue and tile alignment during installation is a simple process. In addition, a floating floor can be installed over a less than perfect sub-floor, provided the sub-floor is level. Either style can be considered for a commercial application, however, due to relatively higher traffic volumes in a commercial environment versus a residential setting, architects are more apt to specify the glue-down floor. It is considered a more permanent installation because of its firm connection with the sub-floor structure.

The most significant consideration in cork floor installation is the choice of adhesive. Cork tiles expand and contract with humidity changes much like wood. Fortunately, the soft cellular structure of cork is forgiving during expansion, therefore, selecting a flexible adhesive is not necessary. But selecting a strong adhesive that creates an instant and permanent bond is important; unless the adhesive creates an instant bond, the moisture in the adhesive is likely to cause the tile to expand during the drying period. This can result in raised corners while the adhesive is drying. It is then difficult to re-adhere the lifted edges.

Using a water-based contact cement has proven most effective in the installation of cork floor tiles, showing a 100 per cent success rate in tests over a variety of surfaces. Contact cement is applied to both the sub-floor surface and the back of the cork tile. It is then allowed to dry completely (approximately 40 minutes). The tile is then bonded to the sub-floor. Positioning can be done by lightly placing the tile on the sub-floor and moving it into place. However, as soon as the tile is pressed to the sub-floor, the bond is permanent and the tile can not be moved.

Installers can create many designs such as perimeters or checkerboard effects by using different cork tile patterns. Unfinished cork tiles can be stained virtually any color with a common wood stain and then finished. On-site finishing is as simple as applying three coats of a water-based polyurethane over the tile surface with a light sanding between coats. Drying time for a coat of water-based polyurethane is normally around 4 hours so a complete floor can be finished in one day.

The finishing touch

On-site finishing is often best for a commercial installation. By applying polyurethane on-site, a smooth overall floor surface is created because the joints between the tiles are also coated with varnish. It is important to use a water-based product as opposed to one that is solvent-based. A solvent-based polyurethane often can create an amber look after the solvent cures.

Cork flooring respond well to water if it is correctly installed. (After all, cork is the most common closure used for wine bottles.) Cork by its very nature will float on water. It does not retain water and it does not mould. Water spilled on cork floors will absorb out through the cellular structure of the material and evaporate into the environment. That said, excessive amounts of water (i.e., flooding) can have a negative effect on cork just as it would on any other flooring material. But typical, everyday spills and wet boots will not affect the floor.

Fortunately, the cork coloring and tile design patterns disguise most scratches and other common floor surface defects. The coloring will also make an otherwise dirty floor appear perfectly clean. Even so, there is a simple trick to revitalize a cork floor after approximately five years under heavy traffic in a commercial setting. Lightly sand the existing polyurethane to create a bonding surface and apply the new coat of polyurethane. If there’s major damage to the floor, a massive tile can be sanded down and refinished completely. Generally this won’t be necessary for 15 to 25 years or even longer.

Cork has been installed on countless sub-floor structures over the years. The most common installations of which are direct to concrete or plywood. So long as the surface is free from major defects that would eventually telegraph through the tile, most sub-floor surfaces are acceptable for installation. Even a floor that is not perfectly level is a suitable sub-floor. The flexibility of the cork tile allows it to conform to the shape of a sub-floor that is not level.

Cork under the floor

Cork is not only a remarkable surface flooring product but acts as an ideal underlayment. Boasting high sound absorption standards and no negative environmental concerns (such as off-gassing), cork sheets and rolls used for underlayment are one of the most universally accepted and specified products. Furthermore, under ceramic and marble cork is used as a thin membrane for stress and crack protection as often specified by those product manufacturers. The cork membranes are resilient, high-load bearing, and will last forever.

Barking up the Cork Tree

Cork is the bark of a cork oak tree grown in the Mediterranean region. The bark tree is stripped no more often than every nine years. The harvest process does not harm the tree in anyway. The tree goes on living to the age of approximately 200 years. Each year the harvest determines the price of raw material, which in turn affects the price of the finished product. Much like oil, the price of cork raw material is subject to many factors beyond simple supply and demand.

After harvest and a curing period where the bark stabilizes, it is sterilized under extremely hot temperatures and sliced into strips used to punch wine corks from the raw bark. Once the wine corks are punched out of the bark, the waste is ground up and used in the production of other cork products such as underlayment rolls and sheets and cork floor and wall tiles.

The exact amount and composition of cork granules tile-to-tile is always close but can never be exactly the same because the product is completely natural. Because of this, when the tiles are cut to exactly the same size one tile can expand fractionally more than another resulting in two tiles of slightly different sizes. It is important to understand this and to factor it in when planning a cork floor installation. The easiest way to correct for expansion size variation is to stagger the tiles (much the same way bricks are installed) as opposed to attempting a grid installation. While grid installations are possible, they tend to be more difficult.