70 years ago cork was a popular flooring choice in a variety of commercial applications including offices, retail stores, restaurants, museums, gyms, and schools. It was used particularly in environments where people were forced to stand for long periods of time. These materials were extremely durable, thick, 4-6 mm thick pieces that could be refinished multiple times in order to remove surface scratches.
The following public institutions feature cork flooring:
- The Department of the Interior Building
- The National Archives
- The U.S. Department of Commerce in Washington D.C.
- Toronto Stock Exchange Building
- Lafayette College in Easton PA
- St. Mary of the Lake Chapel, IL
Over the years, cork manufacturers began to cut costs by making the material thinner, which reduced the number of times it could be refinished. This coincided with an industry switch from a very strong bonding, but toxic adhesive, to a more flexible, eco-friendly mixture, which would occasionally fail, leading to tiles curling and popping.
The resultant loss in reputation severely damaged the cork flooring industry, and between the 1960’s and the 1990’s you would rarely see cork being installed in any public or commercial institution. However, advances in the manufacture of the material as well as increased standards for the industry have led to a resurgence in its popularity and this material is starting to crop up in more locations every year.
Basic Background Information
Commercial Grade Floating Cork Laminates
These consist of 2 mm cork sheets backed by a fiberboard core. the material has a 3mm cork veneer surface, which is then coated in a UV-cured polyurethane wear layer. It is installed as a simple tongue and groove floating floor with a vapor barrier backing membrane, and a water barrier sealer finish that is applied to the surface.
The advantage of these floors is that the wear layer will not scratch or stain, making this material very resilient. The installation is also simple, and it is relatively easy to remove and replace a damaged section of the floor.
Unfortunately, the wear layer will erode over time, and once it is gone the floor will quickly degrade. There are also some concerns about using a floating floor in a public location, as it will not be directly adhered to the subfloor, and may shift slightly when stepped upon.
Solid Cork Tile and Planks
These consist of self-adhesive tiles or planks which can be adhered directly to a subfloor, or installed over a water barrier underlayment layer. The surface and seams are treated with a barrier sealer to protect the installation from scratches and moisture penetration.
The problem with solid cork is that the surface treatment is never going to be as resilient as the wear layer on click together alternatives. Because of this the surface will scratch and mar over time. You may also have a problem with liquids seeping into seams and causing mold and adhesive problems if spills are not tended to promptly.
However, solid cork is often preferred over engineered planks and tiles in public locations because it adheres directly to the subfloor or underlayment, creating a firm bond between the two pieces.
It can also be refinished multiple times, allowing you to sand out scratches and scuff marks, and then varnish the floor to make it look like new. In higher traffic locations, a thicker material should be used so that regular refinishing is possible.
Adhesive Note: Cork does not need a flexible adhesive because the material itself can stand the strains of stretching when it expands. However, it does require a very quick drying adhesive. That is because the moisture in the mix can seep out into the cork and cause it to plump if it does not set and dry quickly enough. Generally, the best practice is to use a water based contact cement applied to both the tile, and the subfloor.
Finish Treatments: A sealing agent will need to be applied to the surface of solid cork flooring. This is especially important in relatively high-traffic, public locations.
A water based polyurethane finish applied to the material and the seams three times after installation is generally enough to create a safe surface seal. This will then have to be reapplied periodically every few months when you notice the sealant surface fading.
Commercial Cork Wax Finishes: Waxing a cork floor is generally not recommended because the maintenance requires the use of large, expensive equipment periodically every 12-18 months. However, in a commercial application, a wax finish can be used if the facility has access to a buffing machine, and someone trained in its use.
The wax will create a nearly impervious coating over the material, which will slowly mar and scratch as time goes by. However a run of the buffer periodically every few months will touch up that surface and make it look like new. The drawback is that once wax has been applied you can no longer refinish the floor or apply a polyurethane finish to it.
Cork Flooring In Residential Locations
Cork As Commercial Underlayment
Often the benefits of cork can be achieved to some extent, without having to worry about the drawbacks of damage and repair, by using it as an underlayment installed beneath harder ceramic, porcelain, or natural stone materials. As an underlayment, the cork will insulate the room from both noise, and heat loss, and will also provide some degree of cushioning underfoot.
The drawback to this, of course, is that cork underlayment is almost as expensive as cork flooring. That means that its use can as much as double the cost of the materials on a job.
Commercial Cork Considerations
Moisture: While cork is naturally resistant to moisture, in excessively wet conditions it will plump, warp, and twist. It should never be used in a public bathroom, sauna, near a pool, or in any other moist environments.
Humidity: Cork flooring generally requires a relative humidity of 45% - 60% or it will begin to expand or contract, causing the tiles to pop up from the installation.
In some cases, the use of a dehumidifier may help to resolve moisture problems.
Level of Traffic: If you install solid cork then you are eventually going to get scratches on its surface. With floating cork you won't get as many scratches, but eventually, the wear layer will fade away and the material will get ruined. The speed and severity of both of these effects is determined by the number of people who walk on it each day. For this reason, cork is generally only recommended in low, or moderate traffic locations.
The best way to offset scratches and dents that will occur in the material over time is to purchase thicker pieces and have it refinished periodically every few years to make it look like new.
Fading: Much like hardwood, if cork is left in direct contact with the sun you will start to see some fading effects. Because of this cork is not suitable for porches, sun rooms, or any external locations. In interior installations, curtains and blinds should be judiciously used to limit this effect throughout the day.
Sound: In certain institutions, such as hospitals, schools,l ibraries, and museums, the level of noise produced by the floor is important. You have to consider both the noise produced by the rapping of heals, as well as that caused by the rolling of casters. Cork works to deafen those sounds, while also acting as a layer of audible insulation against any noises rising up or trailing down through the floor.
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